The Cobb Access Port thread

[David.Yu]

Those of you who have one, post here!

I bought one from Ben Linney last week and it arrived in a very cool iPod-esque box.
I refrained from using it until I went on Wednesday to Surrey Rolling Road in Chobham only 5 minutes from my house.

After some head scratching (and help from A.N. Other person there!), Charlie Wright, the owner of SRR (Vixpy on PH), worked out a tie down arrangement for the straps that didn't interfere with the exhaust or tyres or require the removal of any underbody panels.

We then did a run with the car as it was.

YouTube - Auto-Journals.com's Nissan R35 GT-R on the rolling road

My car has the "no extra power" (or if Litchfield's findings were correct, "slightly less than stock power") Milltek Y-pipe. Quite a healthy base number I'm sure you'll agree.



We ran with the bonnet almost completely closed and on just about the hottest day of the year so far, over 30 degrees. Because I don't have any V-Power near me, my car is almost entirely run on BP Ultimate which is 97 RON.

Charlie's dyno by the way, is known for being one of the most accurate around (Dyno Dynamics) and stock cars e.g. Porsche GT3s etc hit bang on their stated horsepower, although my supposed SAE-rated Z06 made only 498hp on this very dyno rather than the stated 505hp. I say this to pre-empt the sceptics who will say the dyno over-reads. In the US, Dyno Dynamics are known as "heartbreakers" because they always give much lower (read, "more accurate") readings than the more popular Dynojets and Mustang dynos.

So then, with some help from Mr A.N. Other, I attached the Cobb via its dongle and cable, to the OBD socket under the dash, initialised it via the on-screen prompts (which required a fair bit of turning the ignition on and off) and then downloaded the Stage 1 97 RON map (actually the first of two listed, but I've been told one is just a duplicate that shouldn't be there).

This took about 10 minutes and then Godzilla 2 was ready to roll again.

We all waited with bated breath as Charlie fired it up and went for another power run, and the result was....







Not bad for 10 minutes of tuning and the grand total of £750.
But it's not just the increase in peak power, at 4,500 rpm there is a 50hp increase and the area under the curve is vastly increased.

There is also a LOT more torque (although it does appear that Nissan have been massively sandbagging on that number too, with over 490lb.ft stock!) with the peak now being over 530lb.ft!



How do I know that the base figures haven't been completely skewed by the Y-pipe?

Well Mr A.N. Other (who wishes to remain anonymous at this moment) has a completely stock car with stock exhaust and his dynoed on the same day at 506hp which jumped to 541hp post Stage 1 remap.

So yes there was about 6hp difference, but that could just as likely be down to the fact his car has done half the mileage as my car (currently about 2800 miles).

What the Y-pipe does do though is allow earlier spooling of the turbos as they come on song a good 200rpm earlier in my car.

So how does it feel on the road? Simply much stronger, with much better revving towards the top end (where the stock car feels a bit wheezy) and massive mid-range. 6th gear now provides stonking overtaking power and the lower gears are just for showing off!

Basically I am simply staggered that such an easy to use and reasonably priced device can have such a dramatic effect. When I remember the tens of thousands of pounds I poured into Godzilla 1 to get more power...

More driving impressions and of course, Stage 2, to follow!

[peterpeter]

fantastic write up david...keep it coming;

[charles charlie]

Great stuff David, a cracking result and write up.

I jumped straight to stage 2 and the car ran flawlessly. I'd have been eager to see what results you got with that map, but I guess that's for another time.

Back to stock as I'm having the fluids changed this week.

My impressions on the stage 2....

- car feels more silky and smooth at low revs and gears than stock

- power delivery is far more linear and the little bit of turbo lag is far less noticeable, almost non-existent.

- 6th gear pull at motorway speeds is amazing. Might sell my 5th gear!

- Fuel economy seems much improved. Usually on a good blat run, the needle is in freefall, but stage 2 seems less thirsty. (havent recorded any mpgs to compare though)

All in all, as long as the HPCs dont notice this week, I'll be running stage 1 myself until i'm sure my AFR numbers are on the money.

I'm definitely going to look at an etune very shortly just to be safe.

[marcyt21]

im on the stage 2 map which is frankly, astonishing!
im into the 11s on the air/fuel in second, and from then on im about 12.1 to 12.3

[charles charlie]

Originally Posted by marcyt21

im on the stage 2 map which is frankly, astonishing!
im into the 11s on the air/fuel in second, and from then on im about 12.1 to 12.3

What's your tickover AFR, and min/max figures?

And what mods do you have fitted exhaust wise?

Cheers buddy

[marcyt21]

i have a y pipe only
my tickover afr is 14.4, 1st gear flatout is 11.0, second is anywhere between 11.2 and 11.8. remaining gears flatout are like i said, about 12.1 to 12.3

you have the same figures??
be interesting to know as every engine is different being hand built!
marc

[charles charlie]

Yep, same for me (pipe and figures).

I'm gonna look into a custom tune from COBB this week just to be safe.

I believe its around $125 which is great value.

[marcyt21]

how does that worK??

[guycuthbert]

Great write-up David - look forward to your stage 2 experiences too.

Andy - are you tracking fuel economy (using the MFD features)... sounds almost too good to be true; more power & torque AND lower fuel bills?!

[charles charlie]

@marcyt21

Not entirely sure but my guess is that you log your driving with a certain map, then email the log and get a new map in return. Probably do that a couple of time to fine tune everything. I'll let you know what response I get.

@guy

I was too busy going into warp speed to check the mpg figures. I had the MFD on boost and tranny/engine oil temps to be careful so no figures re mpg.

Just so used to watching the needle freefall, but last night took a mate for a serious drive and was surprised to see how little the needle had moved.

Hardly a scientific approach I know, but it was the feeling I got.

Once my juices have been drained this week I'll do some longer term testing and get back to you.

[Zed Ed]

so who's going to take me out for a spin in their Cobb'd car so I can see if it is worth doing?

[charles charlie]

Originally Posted by Zed Ed

so who's going to take me out for a spin in their Cobb'd car so I can see if it is worth doing?

Going near Middlehursts any time soon?

[ScottyB]

Nice write up David, thanks for taking the time to do that.

It is also good to see someone doing a simple before and after run with proof on the same dyno, it helps provide a nice platform for comparing future runs and shuts up the haters.

You may not want to spill the beans too much but what are the plans for Stage 2 or do we just have to wait and see???

CC

What's your plans for the E-tune, are you doing it through Ben or going direct to Cobb?

I have been in contact with them before i knew Ben was going to be euro distributor and have spoken at length about the Custom tune side of things, drop me a PM if you want the history of what we spoke about to save you asking the same questions.......

To answer your question they use 2 types of data for a nice accurate e-tune, both Dyno and road run data emailed to them.

Totally agree with your thinking of having it done, for the cost it is worth looking at a custom tune especially if you start to go down the route of exhausts etc.

[Jm-Imports]

i have been running stage 2 for 9000 miles now....


and am telling you it will rip apart the stock GTRS..

get the cobb bought and a full system fitted..(best thing you will ever do if you own r35)

the car is out of this world..

this week am going to fit my turbo outlets, hks ssqv...

and try and get another map..

hopefully should be 630 to 650 plus..

[David.Yu]

Originally Posted by guycuthbert

Great write-up David - look forward to your stage 2 experiences too.

Andy - are you tracking fuel economy (using the MFD features)... sounds almost too good to be true; more power & torque AND lower fuel bills?!

Thanks Guy. Re the mpg improving (not something I've had the mileage to prove yet), I view this as being more of a "de-restricting" or "optimisation" rather than tuning...