On the track where you could easily keep RPM's above 4000 a larger turbo car would walk all over a smaller turbo car, with the same suspension/tire setup.

 

Stew, ya think? That's my whole point AT THE TRACK OR ROLL "***" RACING....in all other forms it will be pain stacking aggravating and slow and you're forgetting on pump it will really feel like a dog.

Again I say take it to the track (Drag, autox, roadrace) I don't care........ screw this roll racing trend!

 

honk ...... honk........ honk

 

Not necessarily.

You're not taking into account part throttle response and spoolup characteristics that come into play in the corners, although a big turbo car would be kick *** on the straights. On a more technical course, I'd take the smaller turbo, more responsive car over the 600HP for 3000rpm car.

 

Naturally the smaller the course is, the harder it would be to harness the power of a bigger turbo. Agreed.

 

if you look at the competitive time attack cars, they aren't running a 16G or what i consider a small turbo. 3076R being the smallest. granted that is a lot smaller than a gt42R, and to run that on the time attack course would be sort of ridiculous, but with enough wieght taken out of the car, a bit of displacement increase, and a GT35R it would definately be a contender. I don't think running a car with 500-600 whp on the roadcourse is a bad idea. it will require a good driver, but i'd rather be in that car than a 16G anyday of competition.

 

what was this thread about again? oh ya. wow, thats a lot of power... we could see 1000whp this year. i wonder if the mivec head would help with spoolup of these larger turbos...

 

Well, yes, those time attack cars are great, but have you seen their budgets? For the money, and your typical guy running the car on the weekend at the track and on the street the rest of the time, the smaller turbo makes more sense for a couple reasons:

Most of us run the cars on pump gas on the street. I don't care what kind of turbo you have on the car. On pump gas, you're not going to make much more than 400whp.
Most of us weekend guys go to tracks that NASCAR or ALMS run at. This being the case, the best fuel that we can get is usually 112 Sunoco leaded. On 112 octane for 30-45 minutes at a time, I'm not comfortable running more than 24-25psi. Where these GT series turbines shine is way above that and I don't think most of us are dragging 100 gallons of C-16 or VP-120 with us to the track to run 35-40psi on a road course.
At a technical track like VIR, for instance, I can name a couple turns that are a real ***** if the car isn't fully tweaked by 4k, even earlier.

A GT30R car might be faster overall driven by a pro, but it's a lot easier to have fun in a 16/20G/WR car.

But what do I know, I'm just a guy on the internet.

 

On the street...

a 16G cant even make 400 whp on pump. with a bigger turbo like a gt35R you can have a conservative tune and still make those numbers, whereas when your making 350+ whp on the 16G the tune isn't conservative at all.

On the track,

Boost isn't the right measuring stick to base your engines knock or mechanical limit when you are comparing different turbos. It is about CFM, AIT, and eMap, these factors are all different depending on what turbo you run. also, 112 octane is plenty.

"GT series turbines" is a gross over generalization. are you talking about the 30R, the 35R, the 40R? While the 3076R tends to shine at the boost levels you're talking about, the 35R actually performs well (per psi hp gain & response) under a multitude of boost ranges from 10 psi to 30 psi.

But even at 20 psi, the 3076R has lower AIT, and lower eMap than the 16G. even though the 3076R is making more power, the parameters that influence knock are all lower, and the engine is more reliable than the 16G setup making 350 plus. Sure at lower rpm ranges the 16G is producing more torque, but if you were able to datalog a histogram on the track of how much time your engine spends in that range you would be surprised to find that it is actually comparatively small. On these max setups that we are talking about (the thread is about a 900 whp evo) you can also change the gearing which further mitigates the loss in low rpm tq.

If you are on a budget, of course the GT turbo and supporting mods are out of the question, but in terms of pure performance a 16G compared to the 3076R on the road course it really isnt even a question, even on a tight track.

Case in point, the 2005 EVOM tuner shootout at streets of willow robi's car was 5 sec's faster than my car. Although my car was bone stock w/ a 16G, even now with the basic BPU upgrades and suspension it isn't going to make up 5 sec's.

On the extreme end, I've actually tracked my SFWD drag car that makes 600 whp @ button willow. It has a huge T4 PT67 and I detuned the engine to about 450 whp that day. Because the car is light (2000 lbs), and the gearing is tight, I didn't find it laggy or unresponsive at all. In fact it was insanely fast. That's what makes me believe that a bigger turbo (GT35R) could be tuned to work on a road course, especially since the EVO chassis is so capable.

 

This has been argued a countless number of times. The EVO makes a good drag car and also a very good race car. However, I don't understand why someone would waste their money on a dedicated drag racer EVO. There are so many cheaper cars out there than have been proven to go as fast or faster than the evo, and don't cost 20-30K just to buy a stock one. A really good example is the 1st or 2nd gen DSM, which also uses the 4G63T with almost the same exact drivetrain layout. You can buy a 1st gen DSM for about $1500-$3000 stock versus an EVO's hefty $20,000-$35,000 cost. If you have the money I guess you can do what you want, but financially its a dumb decision to drag race an EVO.

 

This year there is going to be alot of 42R powered evo's

 

Buschurs "Black evo" dynoed @ 730whp on their "Mustang dyno". That just proves that "Dynojets" are a "bunch of Bull****".

 

CFM, AIT, whatever your factors are, I'm sticking to my 25psi rule of thumb. Things get real hot out there real quick and I'd rather keep it safe than lean back on a compressor map when I'm looking at the side of a connecting rod.

Going around the oak tree at VIR in 2nd gear, I'm at about 3krpm. If I was in a GT35R car or even a 3076 car, I'd have to left foot brake or double declutch into first and shortshift into second or run with antilag or...just keep a nice responsive turbo on the car.

I'd venture to guess that Robi has about 1000 more hours of seat time than you and those DMS 50 plus aero work plus severe lightening of the car are all contributing factors to those 5 seconds. It isn't all about the turbo out there. It's mostly the driver.

 

Actually, I wasn't the driver, I had my friend Frank Lin piloting the car in the shootout. It was the only stock car in the competition and was faster than 1/3 of the tuner field. the offical time was 1:29.348 secs. Motortrends time in the MR at the same track with a professional driver was 1:34.28 secs.

The biggest factor in the 5 sec discrepancy surely wasn't because of the driver. More like it was down 200 whp from the competition.

If you enjoy bringing a knife to a gun fight be my guest, but the fact is all that torque from 4000 and below doesn't do any good against big top end on this level of competition.

 

The power could have something to do with it, but not as much of a factor as the aero and suspension setup. Robi really has the DMS dialed in on his car and a lot of time at that track.

I'm not saying that 200 more horsepower is ever a bad thing, just that a lot of boys on here see the big horsepower figure, save their pennies for a GT35R or similar and are a lot less happy with the car than if they stuck with a stockish turbocharger with great throttle response.

To be competitive, you have to bring your top game, but for the average guy having fun on the weekend, I don't think it's a priority to have a big laggy turbo. To each his own.