Turbo for road course racing

[millertm]

Looking for experience advice on appropriate turbo setups for track SR20's.

I've got a mild track car right now doing HPDE with NASA. My s14 has a 96' Blacktop w/ T28. I've been collecting parts over the last 6 months for this turbo upgrade relying on shops for recommendations, but I'm getting more confused as I'm about to pull the trigger. I want 325hp without maxing everything out, but I have no desire to ever be at 400hp. I want to keep stock internals including cams (if possible).

I was stuck on the GT2871R .64, but now the shop who will be doing the work says I should just get the S15 turbo and save some money, but then I would max it out around 300-320hp. The GT2871R .86 is an option but the lag worries me.

What should I know. What turbo is best for my desires and road racing application???

[HPballer76]

with that power range in mind it sounds like the 2871r .64 would be perfect for you. it will make the power with some room to spare. i think the stock cams max out around 330 though. what other mods are you planning on doing?

[drftmark]

Sandra - Game Over. I love you sweetheart! (http://www.ziptied.com/forums/index.php?topic=7879.150)

This is a very informative road racing build thread with tons of stories and feedback about road racing an S14. I highly recommend reading ALL of it. He ended up winning the CCTCC championship, beating 500hp vettes and the likes.

You can see some pictures of his car here

SG-Motorsport | Portfolio (http://sg-motorsport.com/portfolio.html)

He used a gt2871r .86 and some other small modifications(i.e just injectors iirc) to the engine. Just make sure your VTC is working correctly if you are going to be keeping everything stock engine wise.

My sr20 is from an s15, so I had the s15 turbo, and the gt2871r .86 that I have now is WAY faster. If you feel that the turbo is to laggy for you, you can get a .64 hotside for around $250 and just switch it out.

[codyace]

.64 gt2871r You will be able to hang with c6 z06's. That's good company if you ask me.

[millertm]

Any truth that a S15 turbo is just as good as the .64, just cheaper?

[HAWAII]

what kind of courses do you run? Do you mostly run short courses with lots of turns with a backstraight that tops 5th [email protected] 120 mph or do you run big courses with not a lot of turns and a backstraight that runs you 5th [email protected] 160 mph?

Two different courses, two different setup

[millertm]

with that power range in mind it sounds like the 2871r .64 would be perfect for you. it will make the power with some room to spare. i think the stock cams max out around 330 though. what other mods are you planning on doing?


555 injectors, PFC D-Jetro & SS turbo lines to support the turbo upgrade. In addition I've got some rear suspension pieces (RUCA) and carbotech XP10 pads.

[codyace]

what kind of courses do you run? Do you mostly run short courses with lots of turns with a backstraight that tops 5th [email protected] 120 mph or do you run big courses with not a lot of turns and a backstraight that runs you 5th [email protected] 160 mph?

Two different courses, two different setup

A 2871r .64 housing will work great for both, as I've been on long tracks (IE: Watkins Glen) and short tracks (ie: pocono south) and both have been fun. (And be super awesome on the street

Even if the O/P 'just wants' 300 hp, I'd still opt for the 2871r, as the top end will be worth any loss in spool compared to the 28r (which will be minimal at best).


PS: Awesome to hear another Carbotech owner :D I love my Xp12's :D

[millertm]

what kind of courses do you run? Do you mostly run short courses with lots of turns with a backstraight that tops 5th [email protected] 120 mph or do you run big courses with not a lot of turns and a backstraight that runs you 5th [email protected] 160 mph?

Two different courses, two different setup

VIR (Virginia International Raceway) and Summit Point (WVa). These are 3 mile courses with good straightaways.

PS: Awesome to hear another Carbotech owner :D I love my Xp12's :D

Last year I was using Hawk HPS pads and they are NOT good for track. At least for someone with as little experience as I have. I hope with the carbotech and some duct work I shouldn't have any problems.

Thanks for everyones comments. I'm leaning toward the 2871r .86 right now. From what I'm told, it gives me the most room to grow between 300 to 350 with out major internal work. Sounds like lag won't be significant. Anyone tell me otherwise?

[codyace]

I'd rather you go with the .64 housing (400 whp capable, better spool than .86) as well.

In regard to brakes: Carbotech pads LOVE LOVE LOVE heat. I will NEVER suggest any other pad to anyone else...they may be more expensive, but they dont' eat rotors, and they last realiativly long.

[deukalionS14]

i agree with the .64 over the .86 too...400~410whp and with E85 you can see as much as 407tq as i did.

Codyace led the way for some of us that made it to 400whp with this turbo.

buuuut i got beat by a brand new Z06....with spray boasting 550whp lol. beat a Camaro SS with mods though! no contest at all

[g6civcx]

What turbo is best for my desires and road racing application???

For roadracing, reliability over all else. You can have as much power as you want but if you break down your day is done.

Second, predictability/consistency and response are more important than peak power. You need to know what will happen every time you step on the gas.

Like you said, you don't have time to wait for lag midcorner.

How many people on Zilvia actually have "roadracing" experience?

BTW, Summit Point sucks compared to VIR.

[TNathe]

I dont think Id be worried about spool when this car is going to be on a 3 mile roadcourse. I'd have to imagine 95% of that track time is going to be above 4k rpms yes?

[codyace]

For roadracing, reliability over all else. You can have as much power as you want but if you break down your day is done.

Second, predictability/consistency and response are more important than peak power. You need to know what will happen every time you step on the gas.

Like you said, you don't have time to wait for lag midcorner.

How many people on Zilvia actually have "roadracing" experience?

BTW, Summit Point sucks compared to VIR.

True, very few on this forum really do.

In reality, I don't run much more than gate (12psi) (sometimes 16 during a single session) on track, and that's PLENTY of power to hold off those bigger cars. As Said above, heat, reliability, and purpose are all very important. Sure I'd love to run around at 20psi all day and really be fast....but I want my car to last as well, and not break.

I'd still take the 2871r .64 over the 28RS if it were my car. Equal spool up, and better top end, all while remaining fun, responsive, and easy on the car.


(Yes, VIR is much nicer than the Point...however I have a soft spot for the Glen hehe)

[g6civcx]

Next to rallying, roadracing is probably the hardest on your car. An average run can last anywhere from 15-45 minutes. Compare that with an average drift event run that lasts at most a few minutes.

I don't know anything about how to make a turbo car survive on the roadcourse. I run a mild NA V8. Good torque response and bulletproof reliability.

VIR (Virginia International Raceway) and Summit Point (WVa). These are 3 mile courses with good straightaways.

This sounds like something a rookie would say. The straightaway is not for you to build up high speed. At least not for your level of roadracing.

Don't try to top out on the straight. The main and back straights at the VIR main course should be used to relax and regain your composure. This is not the time for you to try to break 140mph.

I don't know who is sanctioning your events, but you should let people who have been tailgating you in the corners pass you on the straight.

You may have more power but your first season your corner speed will be slow as hell. It feels fast to you but it's slow for everyone else.

If they're letting you run mixed bags with no passing in the turns you will have a bunch of high grip low power cars pissed off on your rear bumper.

Let them pass you on the straight while you regain your composure.

For that matter, you should not even be on the full course your first time out. You should start out with the smaller half course or even a few autocross events to learn low speed handling.

Last year I was using Hawk HPS pads and they are NOT good for track. At least for someone with as little experience as I have. I hope with the carbotech and some duct work I shouldn't have any problems.

HPS is fine for me but I don't use as much brakes as other drivers. Rookies especially overuse brakes since you don't know where your brake markers should be and how hard you should brake.

Most of the time you will be entering corners with too much entry speed and try to brake and turn at the same time and lock up the wheels.

Learn how to use your brake properly. You should hear just a few screech here and there at corner entry. If you hear a long skid you're not doing it right.

[codyace]

Next to rallying, roadracing is probably the hardest on your car. An average run can last anywhere from 15-45 minutes. Compare that with an average drift event run that lasts at most a few minutes.

Totally agree. This is why at open days they always stress that you should not run your car for much more than a Session, but yo uhave less time of waiting around (more time to change car and get back out). On open days I always just go otu for the regular 20-25, and then come in...no reason to be out for 35-40 minutes ever.


I don't know anything about how to make a turbo car survive on the roadcourse. I run a mild NA V8. Good torque response and bulletproof reliability.

This is the ultimate way to be realiable. If I knew now what I didn't know then...lol!




Don't try to top out on the straight. The main and back straights at the VIR main course should be used to relax and regain your composure. This is not the time for you to try to break 140mph.

Most certainly. Early in the day I'll go out for a good ole top speed run, but that's not every time for sure. I'm sure you understand this, but road racing beats you up (and the car) those long straights are great for wigglying around, adjusting yourself, rechecking gauges...if you're going balls out to top speed you don't have that time. (Although at the Glen in the Fall I like cranking the boost up at the end of my first session to see how fast I can go haha). Rookie move, but as soon as i'm back through the bus stop, the boost controlelr is turned off and I'm off the gate again.


If they're letting you run mixed bags with no passing in the turns you will have a bunch of high grip low power cars pissed off on your rear bumper.

Squirt and park as we say.




For that matter, you should not even be on the full course your first time out. You should start out with the smaller half course or even a few autocross events to learn low speed handling.

or at least an instructor in the car that's competent.



HPS is fine for me but I don't use as much brakes as other drivers. Rookies especially overuse brakes since you don't know where your brake markers should be and how hard you should brake.

Most of the time you will be entering corners with too much entry speed and try to brake and turn at the same time and lock up the wheels.

Learn how to use your brake properly. You should hear just a few screech here and there at corner entry. If you hear a long skid you're not doing it right.[/QUOTE]

[millertm]

This sounds like something a rookie would say. The straightaway is not for you to build up high speed. At least not for your level of roadracing...
Learn how to use your brake properly. You should hear just a few screech here and there at corner entry. If you hear a long skid you're not doing it right.

Not sure if you got the wrong impression from my turbo question, but I'm not really looking for random thoughts on road racing and your theories on rookie drivers vs. experienced drivers. In fact, I'm impressed you pinned me to the use of the word straightaway. You That Guy that laughs at every new enthusist out at the track. I appreciate the book you wrote, but again, I'm looking for experienced SR20 road course users on what turbo they recommend. I think I've found my answer.

[codyace]

To me, whatever you can achieve 300 hp with, while keeping at a reasonable boost level, is going to produce the most fun.

Sure a t28 can do it, but you're really pushing that little turbo to it's limit. As before, this puts the 28RS (in .86 housing) or the 2871r (in .64 housing) as the front runners for me. Both will be fun fun fun, with the spud maybe slightly out spooling the 2871 (slightly as in marginally - you can't look at dyno graphs, ya gotta compare them over time to see the difference). I would still opt for the 2871r with our cars....as you simply have more room to breath uptop. If a Sentra, then the 28RS is the way I'd go..helps keep the transmissions together :D

[millertm]

Thanks for everyone's comments. I'll be picking up my GT2871R .64 next week. I look forward to the install and tuning come mid-April. Hope to see you guys out at the track.

[confuzed240]

I'm sure you will, I'll be the one in front of you!!

[g6civcx]

Not sure if you got the wrong impression from my turbo question, but I'm not really looking for random thoughts on road racing and your theories on rookie drivers vs. experienced drivers. In fact, I'm impressed you pinned me to the use of the word straightaway. You That Guy that laughs at every new enthusist out at the track. I appreciate the book you wrote, but again, I'm looking for experienced SR20 road course users on what turbo they recommend. I think I've found my answer.

No, I want more new people to be involved, but the way you're going about it suggests that you won't stick around very long for many reasons. New driver with high power car showing up at HPDE tends to scare the event organisers.

You asked:

Looking for experience advice on appropriate turbo setups for track SR20's.

I've got a mild track car right now doing HPDE with NASA.
What should I know. What turbo is best for my desires and road racing application???

I already answered your question.

For your level of roadracing, which is novice since you're doing HPDE, the best turbo is no turbo.

If you insist on turbo, make sure you get something small with good predictability and no lag. I suggest a T25. Anything over 100 bhp at the wheels is way too much for your first season. Save your money for tyres, brakes, track fees, and bodywork!

Hell, I only run 225 bhp at the wheels. Any more than that and it becomes uncontrollable. But I don't know anything.

Just go ask your driving instructors what they recommend for your first season.

[codyace]

By all means, lesser power is better power to start, but you gotta think, that if this is his 'two track day a year' and street fun car, then why not build it for what it sees 95% of the time as ya know? Lets also not forget the ability to turn the boost down. A 2871r at 8-10 psi will only be an upper 200 hp car.

My very first track session was in an N/A VVL Powered NX. What a great way to 'break the ice'

Tyres? Are you british today ;) Just bustin :D

[g6civcx]

By all means, lesser power is better power to start, but you gotta think, that if this is his 'two track day a year' and street fun car, then why not build it for what it sees 95% of the time as ya know?

Famous last words. The driver comes in with the same exact mentality: "I'm only tracking 2 days a year. Let's build a fun street car".

Do you know how many of these cars I have seen wreck on the very same track he's talking about going to?

Hell I'm rebuilding a car now that just wrecked at that track.

First day out + Big turbo car = wreck.

The formula has been repeated so many times I don't want to think about it any more.


Lets also not forget the ability to turn the boost down. A 2871r at 8-10 psi will only be an upper 200 hp car

I like the fact that you tune for less power, but 200 is still way too much IMHO for a first time driver.

My very first track session was in an N/A VVL Powered NX. What a great way to 'break the ice'

My first was a Civic with 80 bhp at the wheels. It was a great car to learn car control. You have to carry a lot of momentum or the car will bog at the exit. You get to learn really good things like hitting your brake markers, late apex, hitting your clipping point, and throttle control.

On my current car, I tune the V8 to put out anywhere between 200-250 bhp at the wheels, depending on the track.

For daily street use I tune it right in the middle, around 225~228 to the wheels.

For a short track I tune it at 200 with more low end kick for better response.

For a medium to long track I get closer to the 250 side for more top end power to stretch out its legs on the straight, but I never push the speed since I'm not racing competitively.


I don't really know anything though so if someone wants to chime in then it's all good.

[jasonb]

interesting thread. sorry to bring back from dead, but my situation is just a slight variation and i wanted to solicit opinions from u on turbo upgrade i'm considering.

i have a stock blacktop/t25 in dedicated track/autox car. i recently got a good deal on a 28rs.

my question is this: i don't think i have enough room to bolt in the 28rs with my current manifold so something has to change (if i'm going to use it).

my goals are: reliablity on track (road course), wide power band (from 3k up), and finally, more power than my little t25 i have now. (i agree, breaking down and watching $300 go down the drain while your in the pits really sucks)

should i:
1) get a t3 topmount manifold and convert my 28rs to t3 housing
2) get a t2 topmount manifold and bolt up 28rs
2) sell the 28rs and get a 28rs with the t3 housing already on it (w/ t3 topmount)
3) sell the 28rs and get something else

one thing that is making it hard to decide is i cant' find a turbine map for the t3 .63 housing so i have no idea what the 28rs would be like. (i was thinking i can even use it if i upgrade to a 2871 later)

thanks!
jason

[jasonb]

any love for fellow sr'r who wants to bump it up a few clicks?

graz