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3,684 Posts
Discussion Starter · #1 · (Edited)
Please find below quite a bit of info on the Cobb Tuning AccessPORT, import links for updater, AP Manager and FAQ answered. Mods if poss pls make sticky as this stuff can be refered back to again and again.


GTC, has been the leading global source for high quality Japanese tuning products for over 10 years. Cobb Tuning has been recognized as the leading supplier of advanced vehicle performance engineering throughout the world. GTC has been officially partnered up with Cobb Tuning for the last 18 months to provide the GT-R community with the most advanced tuning systems available in the world.
Over the last 3 months GTC has been working with Cobb Tuning on the European spec R35 GT-R. Hours and hours of road & dyno work to ensure the very best stage 1 & 2 maps.

We have also been testing our UK R35 at Milbrook testing ground ! not a cheap place to go. Simply put you don’t see this same kind of passion and commitment to the GT-R from any other company, especially the Japanese and US resellers who don’t even own Euro R35.

Through this partnership, GTC have immediate and reliable stock of all Cobb GT-R tuning products, starting with the AccessPORT which is available for sale from us now at £750 + vat
The Cobb Tuning AccessPORT is a revolutionary tuning device. Cobb has been doing extensive research & development on their GT-R since February 2008, when they were the first to import this car into the US. Similar GTC were the first to import a JDM R35 into Europe, as has been well documented. GTC were sent a accessPORT in May 2008 for test & feedback.
This system they've developed provides complete control over the factory engine management system, allowing for various tuning options perfectly suited for the GT-R enthusiast. These features include the following:

• Re-flashes ECU through factory Data Port (OBD)
• Ability to uninstall and revert back to original (stock) ECU data
• Ability to store multiple maps on unit, allows switching between maps at user's convenience
• Ability to read DTCs (trouble codes) from the ECU, BCM, Multi-AV, IPDM, Pre-crash Seat Belt, Meter/M&A, and Adaptive HL computers
• Ability to clear DTCs (trouble codes) from all vehicle computers including infamous "Bonnet Light"
• Ability to update reflash maps as improvements become available
• Firmware is Internet updatable (new features may be added as they become available)

This system also comes with various maps pre-programmed in the AccessPORT. Any updates to these maps will be made available from us at no additional charge. * Note Custom maps for specific set ups (i.e anything other than y-pipe/exhaust) will cost extra*

• Stage 1 (for stock cars, including cat-back exhaust)
• Stage 2 (for cars with full aftermarket exhausts, including decat)
• Anti Theft (security mode, car will not start)
• Valet Mode (reduces rev limit and power level, so car cannot be driven aggressively by others)
• Stock Style (normal tune with only speed limiter removed)
• Economy (maximum fuel economy mode, sacrificing performance for better fuel economy)

Please contact us with any questions!

Important: The AccessPORT system is not sold as a "warranty friendly" system. It does have the ability to reflash the ECU to OEM spec which will make it not easily noticed during a Nissan dealership inspection. If you install stage 1 boost is only 0.9 (stock being 0.8) stage 2 boost 1.1

Stage 1 is for a stock vehicle or a vehicle with just a cat-back exhaust. Stage 2 is for a vehicle with high flow cats or cat delete and cat-back exhaust. Must use stock intake.

Stage 1 - 91 Oct - +55HP and +60TQ
Stage 1 - 93 Oct - +63HP and +70TQ
Stage 1 - 97 Ron - +63HP and +70TQ

Stage 2 - 91 Oct - +65HP and +80TQ
Stage 2 - 93 Oct - +70HP and +90TQ
Stage 2 - 97 Ron - +70HP and +90TQ

Check out our videos
YouTube - teamgtc's Channel
Check out our tuning guide
Down load the accessPORT user manual
Down load the accessPORT AP Manager this allows you to manager your maps, to and from the AccessPORT
Down load the latest Updater link as of yesterday (13th July) a new update has been added, you must go to tools and select beta firmware, all Euro R35 users can now run full datalogging parameters, some were missing. This is also the link for many other new updates and features on the AccessPORT such as new software updates from Nissan, we will get them put into the performance maps.

Did you know ?
Cobb Tuning have sold over 2,000 R35 GT-R accessPORT units in the USA alone ! that’s approx 80% of USA R35 owners. Many more have been sold in Japan and South East Asia with great results.
Don’t take my word for it, just google the subject or look on GT-R forum. Owners from Japan/USA report the performance difference is ‘night & day’

Please DO NOT compare this amazing product to anything else on the market. Other reflash companies do not offer a product which the user can hold, use, resell (not like you would need to), unistall before a visit to the HPC then reinstall again, reset your own error codes, do virtual dyno runs, virtual 0-60 and ¼ runs... so easy your girlfriend could install for you.
The AccessPORT is installed on 1000’s R35’s around the world. No one else in the world understand GT-R mapping like Cobb Tuning does. No one else has put in the same £/$ & spanner time, pushed their own car to the limits. Just imagine a year and half head start on everyone else, feedback from users in Asia, Japan, Europe, USA, Middle East.
And just a heads up.. this is only the begining of the ap for the R35. Stock ecu tuning limitations hasn’t even been scratched yet. It is constantly being developed. Every update we’ve seen so far has been FOC free of charge. The possibilities are endless with the right people. We could well see full stroker set ups, fuel system, GT turbo upgrades being run on a stock ecu. Some other stand alone ecu brands already know this and won’t even waste their time trying to compete.
Now lets compare this to another brand, which i will disguise the identity out of professionalism. Mine$ mapping, no thats too obvious, ok techtom, they do not use a dyno, do not datalog. They ask you to rip your ecu out the dash which takes around an hour and send it ½ way across the planet where a generic map will be uploaded. How do i know its generic ? well of course it is they don’t have your car there to datalog. Now this costs how much ? 132,300 yen / £882 + postage. Ok cool you got your ecu back thank god it didn’t get lost in the post and how have 1 bar boost, bit more intake valve timing gently improved to increase torque/spool and high rev limit. Woot woot. Later down the line you want to add down pipes / actuators. Yup its that time again to rip your ecu out yada yada.. wait how does mine$ know what fuel we have here ?

Who uses the AccessPORT other than us ?

Here few independent examples

Cobb Tuning

A1GP / World Series Driver Fairuz Fauzy

David Yu – Evo Mag / Auto journal

EvolutionIV (Alex from Import

Alex showed a very respectable performance at the tuner GP in Hockenheim

Also further testing, man after our own heart

Phillipe in Switzerland

Top Secret Japan



AUTO SELECT ONLINE ƒIƒŠƒWƒiƒ‹ƒp�[ƒc for CBA-R35 GT-R

Sunline Racing

SunLine Racing�^ƒTƒ“ƒ‰ƒCƒ“ƒŒ�[ƒVƒ“ƒO

3,684 Posts
Discussion Starter · #2 · (Edited)
What do the Americans think of R35 GT-R AccessPORT ?

Here is a random selection of independent reviews both good & bad

“I also purchased the AccessPort at that time of its introduction. I almost gave up on it because of the early problem with boost cut-off. I am very happy that I struck it out and eventually I got a custom tune. Dyno results at Forged Performance showed a major hp increase over stock and a 15 hp increase when compared with Stage 2 map after both were tested after replacement of midpipe and catback. The hp increase stayed constant throughout the entire range while the Stage 2 showed some drop-off at the higher revs.

The tech at my dealer knows I have the Cobb installed. He warned me it could void my warranty as I assume it was his job to impart that information to me. Then he just smiled and walked away.”

(note boost issues no longer an issue for over a year now)

“Installed mine a week ago and it is amazing. Torque and HP gains are considerable and are quite noticable. A mandatory mod. “

“best bang for buck period “

“I have tuned a bunch of GTR's now using the AP and LOVE IT!....these cars effortlessly achieve gains with conservative tuning.


“I did my Stage 2 1.08 dyno too and I got 437whp which I would say it exactly the same to yours. Cheers mate! Enjoy it while you can! Run it with HKS 570 kit and Cobbs AP and you'll get over 530whp”

“When i blew my transmission, i removed my exhaust and other mods, the black box picked up everything but the exhaust. the GTR tech that flew down to NY from Tenn was real cool and once he extracted the data from the car which took him about 2 hours or so, he came up to me with a smirk on his face and said well the Cobb Accessport was definately installed then removed (detected boost increase), launch control was used at least 25 times. it doesnt look good for you he said. i told him that is the story of my life.”

Real world

Real World Results - YPipe/YPipe COBB 1/YPipe Custom Tune, Forget the dyno, what does real world data show?

7/1/09, 9 pm Houston time, 90 degrees outside - GT-R with Y-pipe:
0-60 was 3.5
0-100 was 8.3
1/4 mile was [email protected]
60-130 was 10.69 seconds

7/2/09, 9 pm Houston time, 90 degrees outside - GT-R with Y-pipe and stage 1 COBB:

We loaded the stage 1 map and...

0-60 was 3.2
0-100 was 7.4
1/4 mile was [email protected]
60-130 was 9.82 seconds

7/3/09, 9 pm Houston time, 90 degrees outside - GT-R with Y-pipe and Forged Performance Custom E-Tune:
0-60 was 3.08
0-100 was 6.98
1/4 mile was [email protected]
60-130 was 8.72 seconds

1.124 acceleration G's in 1st gear on the FORGED PERFORMANCE etune and LC2

Best bang for buck ?

Cobb Accessport $995 install labour $0 TC $995 50HP $19.90 per HP

Midpipe $800 install labor $80 TC $880 15HP $58.67 per HP

Downpipe $1500 install labor $640 TC $2140 30HP $71.33 per HP

Actuators $550 install labor $1280 TC$1830 20HP $91.50 per HP

Hardpipe IC $1500 install labor $480 TC $1980 10HP $198 per HP

EBC $650 install labor $800 TC$1450 HP ? $1450 per HP

800cc injectors $800 install labor $400 TC $1200 HP ? $1200 per HP

Turbos $6000 install labor $1800 TC $7800 200HP $78 per HP

Exhaust Ti $4500 install labor $240 TC $4740 10HP $474 per HP

So to me, the best route seems like the Cobb and the Mid-pipe are the biggest bang for buck

Mcducks review of Cobb AccessPORT from November 2008 ! (edited as so big) McDuck's Cobb AccessPort review - NAGTROC - The Nissan GT-R Owners Club

So, lets talk about the gains...

first, for those looking at the absolute numbers, keep in mind this kind of dyno reads lower. Sharif says it is not uncommon for a Dyno Dynamics unit to read 8-10% lower than a dynojet under same conditions. He felt the 406rwhp number we hit for stock config was very comparable to the 425-435 numbers we have seen from other GT-R owners' base runs. Also, underpressure confirmed via phone he has seen 406rwhp from another stock GT-R on a different Dyno Dynamics dyno. So we felt pretty good about the base.

The after dynos only revealed a gain of 28rwhp at peak. This hardly stacks up with Cobb's claims of +60hp/+70tq. Even if you figure that is at the motor and take into account 10% for the kind of dyno and 15% drivetrain loss, this would only translate to around 40hp at the crank. What gives?!?!?!?

The answer is simple as you can see from the detailed graphs below. The gains are there, they just are not at peak HP. I have highlighted the **area under the curve** in yellow in both graphs below. Whenever you mod, this is what you really want to know. Peak power is far less meaningful than getting a nice, fat expansion of your powerband.

As you can see from the HP/air fuel graph, the peak HP gain is only 28hp, but the maximum gains (almost throughout midrange RPMs) appears to be right at 60rwhp... exactly as Cobb claims in their advertising for 1.08 / 93 octane / stock tune. More importantly, there is a 40-60hp gain across the power band from 4500 to 6000rpm or so...

Maybe more important than rwhp tho, is rwtq. This is the power you feel and what gets you accelerating. In this case, the biggest gain appears to right at peak torque (approx 435rwtq), but like rwhp there are substantial gains over a wide range, from 3500 to 6000 rpm. And again, as Cobb advertises, the max gain appears to be right at +70rwtq!

Other items of note...
- Air Fuel ratio starts at 13.0 and drops to 11.5 from most of the power range now. Very safe, efficient range for a turboed motor

- Boost was 9-11lbs stock and now runs 10-13.5lbs with Cobb tune

The GTR in Stg1/Stg2 form will always have a hard time up top because of the wastegates. They are pushing 80+% Duty cycle for the boost pressures(12.5 - 14PSi) at redline. This is why you will see cars with upgraded actuators making good peak power numbers. Unfortunately, the labor involved in that swap is substantial.



Streetfire: Stock Run...

Streetfire: COBB Run...

Driving Impressions...


Prior reports are not exaggerated. This tune really brings the 3.8TT to life. I think the most striking part is the power gains are almost completely in ranges you would use on a regular basis... when you downshift or just need a little extra zip when already rolling.

From a standing launch, the car feels stock.... for a fraction of a second! This is probably good since more power at the bottom end would probably cause traction loss and/or wheel hop, slowing initial acceleration and creating stress on drivetrain. After that initial fraction of a second, tho, the car just pins you to the seat. I mean the GT-R was quick before, but not it is scary fast! It really is like being launched from a cannon now... and mind you, that is without switching the VDC-off... just set everything to R, leave in Auto mode, foot off brake, and hammer the gas. WOW!

From a roll, downshift quick and the car catapults forward. definitely stronger from a roll. For those who remember Space Balls, it is like going from Ludicrous Speed to Plaid.

Nothing I can say here can do the acceleration justice. It's just there, whenever you need, like stock, but now it is amplified. Godzilla really roars with any touch of the right pedal. For the price of the Cobb AP, it is crazy not to buy it. This car continues to astound me. I could not be happier with my purchases (car and Cobb). My GT-R is now at 9500 miles and that number is likely to continue to climb... very quickly

LOW MPG IMPACT!!! - OK... after the 'newness' of the tune passed and I settled back into my typical driving pattern, my MPG has risen back to 18.3mpg for mixed driving. It was 18.5mpg before the Cobb, so not much change at all for a substantial power gain! WOOHOO!!! :party:

Why? Well, if you think about it, the biggest gains are in mid-rpm ranges... from 3000 or so and on up to 5000rpm. This is the range you use when you are accelerating aggressively. In normal driving, the car typically shifts before 3000rpm (if you are in Auto mode) and cruising speeds fall from 2000-3000rpm. Since the power gains below 3000rpm are less, there is only a small change in fuel consumption.

Bottomline... you will probably only see a noticable change in MPG if you are thrashing your GT-R around all the time.

midpipe install and custom tune. End result is my car is just shy of 460awhp and sounds great. Net change in dyno numbers today was around 30hp peak and a lot of area under the curve. As usual, great job by Sharif and the gang at FP.

Basically, it stacks up like this... My stock dyno was 406hp. With Cobb Stage 1 v1.08b 93-octane, we hit 434hp. So only 28hp at peak, but there were HUGE gains in the midrange (as much as 60whp in some places).

This time, we started the day hitting a best of 422hp with the Cobb Stage 1 v1.08b 93-0ctane tune as our starting point and finished with 457hp with the mid-pipe and custom Cobb tune for 93-octane. Gain of 35hp peak and gains larger than that in high rpm ranges.

There may be various reasons for the discrepancy between the final pull during visit one and the base pull during visit two... different days, different temp/humidity... first visit no mid-pipe, second visit mid-pipe baseline before tuning for it. Who knows. My guess is if yesterday had been a cooler day like my first visit, we would have seen 5-10hp higher readings.

For sake of argument, we'll be conservative and assume the base runs yesterday with Stage 1 tune were lower than 434hp because the midpipe was added and not yet tuned for. Under that, our most conservative assumption, I gained 51hp at peak (457-406=51) and bigger gains in off-peak areas of the curve. Not bad given the low cost of these mods.

Here are the latest dynos. The first just shows the actual, same day gains we realized going from Cobb AP Stage 1 v1.08b tune for 93-octane... to Cobb custom tune with mid-pipe...

and here are the graphs for total gains since I first visited Forged Performance. I've highlighted the same graph showing net improvement to area under the curve for both HP and TQ. Essentially, this represents pure stock to custom CobbAP tune (for 93 octane) with aftermarket mid-pipe installed (the midpipe is a piece FP is developing with another vendor... name and details to come). At this point there is a lot of significant improvement in output in mid to high range RPM... as much as 50-70hp in some areas of the powerband. Net investment for all this goodiness... under $2500

I cannot say enough good things about the upgrades and quality of work from Forged. Next on the agenda... finding out what these improvements translate to in the real world!

whp improvement...


3,684 Posts
Discussion Starter · #3 ·
Custom mapping with AccessTUNER

GTC has just invested in the new AccessTUNER software for the European R35 (only just released).

We do not buy maps from the USA, we own the AccessTUNER dongle and will be offering custom tunes, which is an effective method with the Accessport because of its excellent datalogging.

How to datalog with your ap ? AccessPORT Feature: Datalogging

When you datalog for us we ask that you go into the datalog parameters to select and add a few more from original settings

First List:
Ignition Advance
Load Timing
Load Wastegate
Wastegate Duty
Boost Target
Boost Error
Throttle Position
A/F Correction B1
Injector Pulse
Air Fuel Ratio

Vehicle Speed
Mass Airflow
Exhaust Cam Adv
Intake Cam Adv
Intake Air Temp

Also for those worried about the ‘W’ word we are giving away a free custom map with every accessPORT sold – we have developed Stage 0: no boost increase, improved fuel eco (less black soot on tail pipes). Will also be suitable for Y-pipes.

Although that said no one we know of overseas has put stage 0 on their 35’s :p

For anyone who chooses the amazing world’s best exhaust GTC Titan we will also look at your data logging and make adjustments at no cost

Tuning with the AccessPORT FAQ (data collected beween us, Cobb Tuning, John Shafer and other sources)

In stock form, the GT-R runs extremely rich (over fuelling) across the RPM range, in particular the turbo spool area at around 2,500->3000 rpm, and so rich after 4,500 rpm, that the Dyno’s Wideband O2 Sensor max’d out at 0.68 Lambda. This is most certainly an overcautious safety condition, typical of most mass produced performance cars. Stock Boost Pressure was generally recorded at around 0.8bar max at 3250rpm, with fairly efficient boost control, dropping off to 0.6bar at the top of the RPM range. Physically, the compact engine bay is very well designed with the low slung twin IHI Turbochargers hidden on the hips of the V6 VR38DETT unapparent from first glance under the hood. The stock exhaust system is of average design, not especially great exhaust gas flow (will highlight this in another exhaust post) but the with the presence of 4 Catalytic Converters (2 per bank), small diameter pipework in sections, and ‘Bolt-On Tail Pipe Trims’, there are a great deal of improvements to be achieved, simply put the VR38 is a caged beast.

What is the mechanical configuration of the vehicle?

The Stage1 calibrations are designed for vehicles with a stock or axle back exhaust system. The Stage 1 Cobb mapping was designed to optimize the ignition curve for 15PSI of boost. The Primary Fuel targets were also leaned out for optimal performance on varying octane levels. The OEM mapping for the GTR did not have any Exhaust cam timing. Cobb developed a map that optimizes volumetric efficiency under varying conditions.. Through rigorous testing we arrived at a set of intake and exhaust cam timing maps that work seamlessly together for increased power and fuel economy.
The Stage 2 mapping is designed for vehicles equipped with a full exhaust system and drop in filter element replacements. Hi flow catalytic converters are encouraged for the down pipes. The Stage 2 mapping takes these techniques a step further. We are able to be a little more aggressive with boost and timing. The fuel curve is also modified for the quicker spool characteristics of the Stage 2 vehicles.

-Stage 1= a STOCK GTR or ONLY an axle back exhaust. NO intakes. Fully catted.

-Stage 2= CATTED Downpipes, and a full exhaust (can be catted or catless mid) Y- pipe ok. NO Intakes. Drop in filters are OK. Intercooler pipes are OK.

Why should i buy an AccessPORT ? I’m happy with my Y-pipe it sounds great!

Good luck, the extra money you will spend on petrol from poor fuel economy will well pay for an accessPORT in no time.

Should i uninstall my AccessPORT before Nissan HPC service ?

It’s a good idea, simply because Nissan technical releases software updates which the HPC loads onto your R35 ecu via the consult III, these updates are no very regular maybe 1-2 a year. Should your AccessPORT still be installed when the HPC tries to flash update you will lose the performance map and have to send your AccessPORT to sort out. GTC and Cobb Tuning also have access to these official Nissan updates via Nissan Techical, so this means when we have an update we also make it available via the updater link, so your performance map will also have any updates from Nissan. Sounds good eh ?

In the real world it takes ages to run though what your 35 has been recorded doing, most HPC are just more interested to see if your 35 has seen high gearbox temps so they can charge you £xxx for new oil.

What fuel ?

-If you are running 97 ron super unleaded or better, the Stage 2 **91/93/97** mapping is OK. On pump, I would start at the Stage 1 and data log the car. Be sure your AFR (on the AP is at 12.0 or richer). The factory wide bands reading considerably leaner. It can at times be a full point off in A/F Ratio. This is not too uncommon as we've seen the same phenomenon occur with some other Nissan vehicles as well as the Honda and Mazda platforms. On an external wideband sensor, the AFR will be 11.3 - 11.5. Then you could try the Stage 2 mapping, look for consistent timing (lower at peak TQ, scaling up to redline) and AFR in the same range. Higher ron fuels support more ignition timing, higher boost levels, and leaner air to fuel mixtures compared to lower ron. Using a map designed for high octane with low octane fuels can produce motor damage. The ideal air to fuel ratio depends upon fuel quality. Higher octane fuels are more detonation resistant and therefore can be run at leaner air to fuel ratios. Leaner Air to Fuel ratios produce higher power but also create more heat. Excessive heat can lead to detonation. Lower octane fuels such as 95 ron are more prone to detonation and therefore require a richer air to fuel ratio. Rich air to fuel ratio combustion produces less heat and therefore less detonation. We have found that the GT-R motor can run mid to high 11 Air to Fuel ratios when running quality fuels. Lower quality fuels require mid to low 11 air to fuel ratios. If the vehicle is detonating for an extended interval, the ECU will try to protect the motor from permanent damage

Can I use an octane booster to run the higher octane maps?

-The short answer here is NO. None of the maps have been designed to work this way. There are far too many variables.

What is the most boost I can run? What is peak boost?

-This really depends on what level of modification your car is at and what fuel you are running. A safe reference point is 1BAR on pump and 1.2bar on super unleaded (97 ron or better). A Stage 1 car will be very happy at 1 BAR and a Stage 2 at 1.18BAR. So, if you are willing to run super unleaded, BP Ultimate is my choice (and not saying that as they sponsor GTC), then you can gain some headroom and run higher boost. The stock fuel injectors are ~550cc. These vehicles can create enough airflow run these injectors at or above their maximal capacity at approximately 17SP or 1.22BAR (AFR 11.8). This is particularly true for vehicles equipped with high flow exhaust systems and intercooler. Be cautious about running out of injector on similarly equipped vehicles. (larger injectors are now readily available)


The stock turbo charger can produce boost levels in excess of 20 psi. This is enough cylinder pressure to cause engine damage. Accesstuner mappers are cautious when adjusting boost control parameters. Be particularly cautious when any mechanical component of the boost control system is altered. The AccessPORT can hold boost well, so do not be too concerned by what you just read. Many people are fitting boost controllers which is fine but refer back to above message regards the stock ecu will try to protect the motor from permanent damage from det / knock, ecu will not be able to pull back the boost when a boost controller is fitted.

Tell us more about the GT-R boost system!

Sorry its far to in-depth and complex, and we need to keep some secrets.

Do I really need actuators?

-Actuators are the second best mod you can do for your GTR (aside from an AccessPort of course). They will allow you to hold greater boost levels at redline. The current Off the Shelf maps are NOT designed to run high boost levels at redline. YOU MUST HAVE A CUSTOM TUNE!!! The simplest explanation is that you will run too much timing and not enough fuel. The other thing to consider is that actuator fitting is a big job 1 day +. But grin factor is something else ! Forge Actuators allows for higher boost levels, less boost tamper, and
more power. But are still reaching the limits of the stock turbocharger and injectors. At about 18psi sustained boost is seeing the stock injectors maxing out 100% duty cycle, which delivers about 525whp (baseline stock is 390-400whp). Upgrading to larger injectors is very straightforward. For those that want more power, a turbo upgrade is the next logical step. The stock OEM turbo’s are rated at about 30 lb/min worth of air each, so should see 600bhp out of them. Based on experiences on the dyno, tuners are seeing about 525whp. The turbo upgrades coming onto the market, will flow 40 lb + worth of airflow, which would give a maximum power of 800bhp.

Do i need to replace spark plugs ?

-It is recommended to go colder range when pushing over stage 2 – 535whp.

Is the TCM (transmission) made of glass, or can I push it?

-To be honest, no one really knows yet. There are plenty of rumours out there, but I have never broken one yet. We all know early cars dropped like flies due to a number of failures, one being the solenoids. But then some US tuners are running 700WHP without issue

Does going to catless downpipes/turbo outlets really affect my tune?

-YES!!!! It makes a huge difference. It will dramatically affect the spool characteristics of the turbos. You will be able to hit full boost earlier, thus entering a lean spool condition. To put it simply, spooling earlier will lean out the tune at peak torque. Not good. You should consider a custom tune at that time.

I can’t wait to add an induction kit to my GT-R !? My last car intake gave me 100bhp

Hold your horses, the OEM intake is world class good. We do not recommend to change it. Many on other side of the pond have actually seen power de-crease by adding aftermarket intake. Cobb Tuning offers maps that support the stock intake only. Should you wish to go aftermarket intake you will have to go through a deliberate process to create MAF sensor calibrations. The MAF sensor readings depend entirely upon the type of intake system. After market intakes rarely promote laminar airflow around the MAF sensor that is equivalent to the stock system. As a result, the stock MAF sensor calibration is not appropriate for most aftermarket intakes. If an aftermarket intake is used the tuner will have to spend considerable effort to ensure that the MAF sensor scaling matches the true airflow characteristics of the chosen intake. We highly suggest that the initial tuning is done with the stock intake system so that a proper tune can be established with a known MAF sensor calibration. Once the tune is optimized for the stock intake the aftermarket intake can be installed and only those components of the tune related to this intake change need be altered.

Can a CEL(check engine light/ECU code) really hurt performance?

-Yes. The real downside here is that you may not even see the code!! There are two primary symptoms you should look for. 1.Low boost. Suddenly, your car is performing poorly and is hitting substantially lower boost levels., 2. Significantly richer AFR under load. If you see that your AP was logging 12.0AFR under load and now you see 11.4, that is a big red flag. Go into the trouble shooting screen, take note of the codes. Reset the ECU.

So all this talk about Cobb Tuning !!! But who are they ????

Well when they are not busy hacking manufacturers ecu’s they do take time out to have moustache / mustache competions !!! ye ye i know don’t ask me it must be an Amercian thing lol

Some of you know / have been chatting to ECU Guru Joe Graham, so he can be first. Sorry Joe haha

Gary Sheehan, Marketing & timeattack driver

“Turtle” Wong Engineering Manager

Jon Pomrenke ecu guru

Matt Gauthier Firmware Engineer

Christian Krahenbuhl Sr. Calibrator

Dan Brumett Technical Support

(Very rarely an ap may see a fault and if we can’t sort it in UK then Dan is the man who will deal with getting you a new one within days)

You can see the full list of Cobb ‘competitiors’ here COBB Tuning Blog sadly Turtle didn’t win, but she got my vote J

Cobb Tuning have over 20 staff inc CEO Trey Cobb, who didn’t take part as he’s too busy giving interviews

Ok ok enough already i get the idea, i just want an AccessPORT ! where from ?

Get in line, near 50 went last week alone ! But we plan to keep good stock levels. We expect to see similar numbers (2000+) sold as seen in the US and Asia.

First and foremost GTC are distributor and part manufacturer, we can install / supply direct but we always where possible support our dealers and encourage to buy from one of our approved dealers.

Other than us. We also supply some HPC’s around Europe inc Nobles, Visscher (Holland), Broemmler (Germany). We also highly recommend buying from Alex @ we like guys who run the parts they actually sell on their own cars they own ! Full dealer list can be seen on our website.

3,684 Posts
Discussion Starter · #14 ·
Thanks guys.

small request, if you like this thread pls rate it out of 5 * at top of post.

If you think post should be sticky say so, trust me you'll be coming back time and again to the above updater link, speaking of which a new update has just last night be added for improved JDM and EDM logging. JDM just update as usual EDM as above tools-beta firmware. No need to reflash again to make updates work as ap reads ecu RAM directly.

Tokyo/Antony have you tried virtual dyno yet ? :D

btw i got the video of Philippe 35 wrong its meant to be this one


3,684 Posts
Discussion Starter · #33 ·
I need to speak to Ben about this, hearts saying yes yes yes but sensible head's reigning me in.
Anyway if i do can i run stage 1 and 2 with middlehursts (milltek) Y pipe or just stage 2.
Also if i go this way i'll defo go for the custom tune, anyone know how much this is and also how is this done.
also people talking about AFRs. is a higher no. lean or rich id assume lean
Stage 1 recommend stock oem exhaust and mid pipe

Stage 2 works well with Y-pipes

Don't worry these free maps are also rich and designed for safety

When you get into the custom stuff nets more power depending on modifications on your car.

We can create a custom tune specific for your R35 based on a series of datalogging either in person or we can do via email. Both effective. This can take as long or as short until we are all happy. Have a read of the datalogging linky on page 1.

To be honest as many already understand stage 1 & 2 are already very effective, so we recommend only go for custom tune when going stage 3 i.e turbo outlets, actuators etc...We're not here to charge for stuff you don't really need :) ask Scotty B how much stuff i put him off from getting :p

3,684 Posts
Discussion Starter · #48 ·
autoselect stage 1 custom tune ;)

i have this map from them, its nice timing pulled.

@ Nismo :chuckle:

i reckon nismo ecu won't even come to euro zone. 350Z Nismo stuff was only really aero.

3,684 Posts
Discussion Starter · #49 ·
notice the high RPM boost taper in that video. looking to get consistant boost all the way from 4000-7000 RPM, a nice flat boost curve using a flat wastegate duty cycle

you'll notice the same with a stock set up, never had boost fall off like it does on the new GT-R.

3,684 Posts
Discussion Starter · #51 ·
Hi Rich,

how's it going ? any more pod runs ?

I havn't spoken to AS about these runs, ive only just saw this video today on their youtube page but can say that first run won't be stock power for sure. I can check we converse quite alot.

Similar i don't know what exactly they're changed in the map as its locked and we wouldn't open it anyway out of respect for their interlect property and not that we'd need to anyway.

Some nice improvments can be made in a custom tune and we're giving Cobb Tuning alot of feedback on what we'd like seen in the soft & logging etc..every few days been making nice advances, in fact Joe is probably sick of us lol

Week just gone was spent starting etuning a JDM 35 in India fitted with GTC turbo outlets, actuators, ti y-pipe and exhaust. Without custom map he saw boost spike & safety mode cut. Custom mapping got this undercontrol, good drivability and top end power...and most important safe afr.

Sorry no dyno graphs as no dyno in his area.

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Discussion Starter · #54 ·
We spent day on dyno yesterday custom mapping Fairuz JDM 35, sporting bran new BBS Gold rims :D

Previous seen results on dyno dynamics

Stock R35 476hp (380ATW) on dyno dynamics

JDM R35 with GTC 3" y-pipe 486.3hp

EDM R35 with GTC 3" Y-pipe + exhaust 542.7hp

66.7 hp increase with accessport stage 2 + y-pipe & exhaust

Yesterdays testing

Hooked up with det cans, AFR sensors at tail pipe -accurate reading as no cats on this car.

JDM R35 2,800 miles with GTC Y-pipe, GTC Turbo outlets/Down pipes.

OEM map 532.4hp - impressive power increase, proves VR38 is caged beast and needs to be set free, but runs on lean side without suitable map. turbo spools faster with increased flow.

Cobb stage 2 shelf map 560.7 hp running 1.1 bar boost - this nice 18hp increase over stage 2 map + y-pipe. But again runs lean without suitable map for turbo outlets !

GTC custom tune 571hp (460ATW) running 1 bar boost - we decided to stick with 1 bar boost but improve other areas

We'll do more runs with higher boost soon. More to come with more time on dyno inc improved top end

so bascally that 570hp figure is quite similar to what is seen with HKS 570 kit which costs £3,500 + vat + 22 hours fit time (mostly down to bumper off engine out actuators, boost controller, cooler pipes)

or just buy accessPORT £750, gtc y-pipe £350 and gtc Turbo outlets £450, custom map £350 total £1900 + vat + 4-5 hours fit time

Ourselves, Forged and a few US tuners already proven HKS pipes not necessarily needed, bigger core is more important (pipes can pop off tbh, but heat soak not big issue). Ap controls boost well at 1 bar and controlls fueling. stock actuators ok at a bar also.

Selection of pics inc dyno strap down, which may help other people out

Det can

Faiurz happy

Will shortly do some real world testing. Would like to do a trip to Santa pod to see if this 35 can dip into the 10's. Fairuz reported his 0-60 on ap was 2.9!!! and shot one / two flames on gear change. Or if any mags want to sort us out with Millbrook again :wavey:

3,684 Posts
Discussion Starter · #56 ·
yeah i love Japshow Finale, something special about that last date in October last few years (except for last oct when it heavy rained) but two years previously skyline we imported duke R33 smashed the 8 sec 1/4 record and won competition

Forgot to mention we did so many reflashes that at one point the battery died and ecuflashing stopped mid way though. Luckly the ap can recover itself and once battery charger added we could continue. But word of warning always use a battery charger just in case !

3,684 Posts
Discussion Starter · #60 ·
Nice! So is that with the de-cat downpipes v stock downpipes?

What was the max power?

What happens come MOT time? A lot of labour to put the stockers back on isn't it? Are you looking at sport cat options too?

Yes Dave ! sports / high flow cat

Those who want to make the effort will have a 35 that sounds as close to a 'Ferrari' V8 as possible

3,684 Posts
Discussion Starter · #64 ·
12 most important info possible relevant to remote tuning:

Ign Advance
Theo Pulse Width
Load Wastegate
Wastegate duty
Boost error
Throttle position
Mass airflow B1
Injector Pulse
Air fuel ratio
Vehicle speed

Note with EDM shelf maps Cobb Tuning did not include intake and ex timing improvments, so for the custom maps we'll get an improvement at 3000-4000 RPM with more intake valve timing and wastegate duty, at the top should release a bit more power, and help spool.

Lot's more to come next few months :)

3,684 Posts
Discussion Starter · #65 ·
COBB Tuning is conducting a public 64-bit beta test for AccessPORT support software applications, AP Manager and AP Updater. The new 64-bit applications will be compatible with 64-bit versions of Windows Vista and Windows 7. This new beta software is also compatible with Windows 7 32-bit operating systems.

To download the 64-bit support software for the AccessPORT, please visit and complete the 64-bit Beta Testing Download Page software request form Cobb Tuning. You will receive an email with instructions for download.

Please report any 64-bit related software issues via email at [email protected]. A Known Issues Page will be updated to show which issues have already been reported along with the resolution status of each item.


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