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Discussion Starter #1
I’m sick of people bitching about turbo lag.

It’s a thing of the past with current turbo and gearbox technology.

I think your just in the wrong bloody gear and you can’t drive!!!!!!!


It would interesting to see people’s views on lag and how it is determined.

Some people would say it’s the time the turbo takes to spool up to maximum pressure and some would say no that’s maximum boost threshold and lag is the time the turbo takes to come back in after you have let go of throttle and then your back on it again. Or could it be both?!
 

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For me it's how the power is delivered. I had AMS billet k16's on the Porsche and the spool was immense, it didn't make big numbers, but they were on full boost by around 2.5k and i loved them. You could drive it anyway you wanted and the power was just everywhere.

I had a similar conversation with a chap that builds engines, he's driven loads of 1000+hp cars built to customers spec and you put your foot in and nothing, then this massive surge of power, which by then the lesser car is down the road, but people want those big numbers.

I had a TD04 on an old track car and the spool was instant, i wanted that headline figure so opted for a VF35 which got me over 300hp, first time on the road it felt great, but on track the lag was very noticeable, you can drive round it as much as you like but again, nothing, massive surge, barreled into corners totally unsettling the car, hard on the brakes, was just terrible, once i was back on the road it was more noticeable after that.

The current project is a 4.0L with Alpha 3076, even with those i'm worried about the possibility of lag, but i'm hoping the extra capacity and porting will be able to spin them a bit quicker as above everything, i want that driveability i got with the Billet K16s. If i hadn't done a stealth and had an unwelcome visit from the rods, they would still be in, but alas the way they hit, it was only a matter of time.
 

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I consider lag the revs / exhaust gas needed to get the turbo going. And transient response how long it takes for the turbos to get back on it when you have taken your foot off the gas, at higher revs. I think dyno's can flatter big laggy turbos as they can hold the car back making it appear to boost earlier than it would on the road. The transient response is only measurable when on the road.

I believe turbo tech has come a long way since the old days and engine capacities seem to have inflated in our world (no bad thing).


I would have thought Sim, that if you're talking about a 4lt GT-R with twin alpha GT30's, then this will be absolutely fine for both lag and response. The only issue will be holding onto it when it comes on song.

You've seen my build thread and the turbos I'm going to be running. I'm anticipating these to be somewhere between GT30 and GT32 spool and response but with more power potential.

If I had stuck a pair of GT35 or bigger on, then realistically the thing will be a pig on the road with standard capacity and probably not spool until 5k+. That, I think would be considered laggy as hell and with slow response - BUT, I haven't been in one and don't actually know.

It's all subjective based on your own experience and what you consider ok. Most people just say what they have is amazing so you can never be too sure. it's when you see solid results and feedback time and again that you can start building confidence.

I intend to give an honest review in my thread. If it isn't what I hoped for then I will need to make some further modifications. The package has the potential to perform as the turbos are not that big in the grand scheme of things.
 

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Nick

You mentioned on the GTR vs 911 Turbo S thread that you had a run out with the Battalion down to South Mimms in your 997 that proved quite a lot, what did it prove exactly?

You also beat some supposedly high powered GT-R's in your lower powered Porsche, why was that? in my view, they were either not making the quoted power, or your car made better use of the power it had. Porsche have always had a massive mid-range punch and quick spool, that's how they are made and that's what makes them quick, some of their dyno plots look like a high powered diesel.

Also, gearing. Manufacturers spend a lot of time designing their ratio's to complement the engine characteristics, if you change them, then it's a lot easier to find yourself in the wrong gear. I found this with my westfield, i ended up changing the entire gearbox.
 

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Discussion Starter #6 (Edited)
Nick

You mentioned on the GTR vs 911 Turbo S thread that you had a run out with the Battalion down to South Mimms in your 997 that proved quite a lot, what did it prove exactly?

You also beat some supposedly high powered GT-R's in your lower powered Porsche, why was that? in my view, they were either not making the quoted power, or your car made better use of the power it had. Porsche have always had a massive mid-range punch and quick spool, that's how they are made and that's what makes them quick, some of their dyno plots look like a high powered diesel.

Also, gearing. Manufacturers spend a lot of time designing their ratio's to complement the engine characteristics, if you change them, then it's a lot easier to find yourself in the wrong gear. I found this with my westfield, i ended up changing the entire gearbox.

It proved to me that the Porsche is king when it comes to mid and top range speed runs when comparing to stage 4s and 5s r35 Gtr***8217;s.

Which kind of shocked me to be honest that is all.

My Porsche was dynod on a maha in Germany where I had it built. It was 650ps and 935nm.

The only thing I***8217;ve raced quicker than my Porsche was the r34 I have just built which again I was shocked by.

The Porsche had the edge on hitting full boost etc but in the correct gear in the r34 it would gap it like a fiat lol

It***8217;s only my experience bro.

Obviously you would have to be there to see the outcomes.
 

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How did yours compare to Range***8217;s 34 Nick, didn***8217;t you both have a run out together?
From what I***8217;ve seen, his seems to be quite a good fast road package.
Mine can be quite laggy when not in the right gear but it depends on the individual interpretation of lag I feel.
 

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Discussion Starter #8
How did yours compare to Range’s 34 Nick, didn’t you both have a run out together?
From what I’ve seen, his seems to be quite a good fast road package.
Mine can be quite laggy when not in the right gear but it depends on the individual interpretation of lag I feel.
From memory mine is a lot faster. But I’m not sure if his spec has changed since then or if his car was running 100% properly to give a fair judgment on the night we went to the autobahn.

When I watched your video with your car on the country roads it seemed pretty awesome to me.

Check this out for a laugh lol ;)
 

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From memory mine is a lot faster. But I’m not sure if his spec has changed since then or if his car was running 100% properly to give a fair judgment on the night we went to the autobahn.
Not seen it for probably getting on 18+ months tbh, I’m at the track every weekend when I’m home these days, probably only driven the Skyline a handful of miles in that time.

When I watched your video with your car on the country roads it seemed pretty awesome to me.
That’s a very old video, the car was only running watergate spring pressure (0.7) - the focus then was getting the gearbox setup correct; that’s what makes the car for me, I wanted the transmission spot on before running more power.
Ultimately there is always going to be lag because the turbo is quite large (now a GT47 core) but the gearbox makes it hardly noticeable in anything but 1st gear if you’re pushing on.

Check this out for a laugh lol ;)
Haha, awesome, sounded a bit like Lenny Henry commentating :D
 
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