S15 T28 vs Disco Potato...which one and why? other suggestions welcome :)

[Daemos]

So I have a few people looking @ 1989-1990 180SXs from japan for me to ship over to Canada.

so I should have one right after winter ends or sometime during the winter.

Some things I would like to do is upgrade fuel, ecu, etc.

I think I kinda got the other parts figured out FC injectors, power FC, Z32 AMF...fuel pump etc etc...

But I haven't been able to decide on a turbo.

I'm looking for something that's pretty quick spooling and good for ~300whp (which with slicks should get me into the 12s, maybe even on sticky street tires)

Basically what I'm mainly more concerned with is response and top end power. Since a) I am an autox junkie and throttle response and instant torque is kinda important b) I hate getting passed, or not having enough top end to pass people., and I hate having to say race someone, then have them pull away later because I don't make enough top end power. IE like me (spec v) vs RSX-S, 1st and 2nd gear I'm ahead by like 1-2 car lengths because of mad torque (lol yea right...) then I hit 3rd, and the RSX-S will pass me like I'm stsanding still (mad vtec pull yo hahha) But I want ot have a nice usable powerband that's good for autox and drag (But I like autox alot more than dragging) and streetability as well is a must.

Someone also suggested I go with a Turbo like the GT2540 or the GT2535, but I would imagine they would be pretty laggy and have poor throttle response...

I'm also looking for something that can bolt on to the stock turbo manifold, too lazy to frabicate my own here (I know badddddddd me)

So with this in mind it comes down to the S15 T28 and the Disco Potato (I'll take other suggestions as well...if they're better than these two)

[soflajdm]

how about the FP big28?

[cosmo]

Check out SCC's project silvia. they got the DP on there, and after reading some compressor maps, and hearing Mike Kojima talk about the DP, I am completely sold on that turbo for my KA

[Def]

Get the S15 turbo. A CA would have alot of trouble spooling up a 0.86 A/R turbine GT28RS(Disco Potato), and they are available in 0.64 A/R, but that's not common at all.

The S15 turbo will flow out about 290-300rwhp on an SR, so you could get close to that with tuning and lots of bolt-ons.

I'd imagine a CA wouldn't hit full boost on a 0.86 A/R DP until 4.5k RPM, and it really doesn't have much more power potential than an S15 turbo.

[Daemos]

hmmmmmm I thought the DP was the turbo to elimiate superchargers?

http://shop.store.yahoo.com/ch....html

it says it comes in a .60a/r and a 62 trim, but I'll go and assume it wont' beable to make as much power as the .86/ar and 72 trim...

How about the GT2530/35 turbos?

[cosmo]

Don't worry about the .86ar. I thought the same thing when I saw that, but when I saw the compressor maps and the dyno chart of SCC's car and saw that was almost like a t-25 (spool wise) with a wicked top end.

The S15 and the DP have very close spool times, but the DP has better boost response

[Ichi-Go]

Well the lower A/R turbine would help a lot. I think that even with the .86 it would spool by 4 grand. SCC loves that turbo I think Dave Coleman sleeps with one. They are using it on all there project cars now. Project 300zx is getting two of them. He said the SR has no lag at all and if you look at the dynoe chart it follows the T25 power but keeps going up. I can scan the dyno map later tonight. I would think that the lower A/R housing would work very well with the small CA18. It also bolts right up to the stock mani and should be good to 350hp. It could put out 20psi at 9 grand I am sure. I want to get a compressor map and plot some CA points on it.

[Daemos]

so the .86 is okay? I'm trying to get a really responsive turbo, because autox and cornering is all about response and low lag time.

would the .64/60 (whichever it is) beable to make as much top end as the .86?

And could you post the dyno chart? I never saw it

I'll see if I could find the compressor map for the DP, how much of a diffrence would there be between the .64 and the .86?

[Daemos]

I found the compressor map...

here's the thing out of the garrett catalouge (I found a pdf file, and have a print to image option which didn't turn out so great haha)

but here it is:

http://members.shaw.ca/daemos-/discopotato.jpg

And here's the compressor map:

http://members.shaw.ca/daemos-/dpmap.jpg

[boost_boy]

Don't think about the .86 A/R. Your CA doesn't flow enough CFM like the SR does, so your response times will be much later in the RPM band. You will have top end, but at the expense of bottom end response loss. The .64 might be your best recourse. you'll lose some power on the top end compared to .86 A/R, but you will spool much quicker. Would be even sweeter if you could machine the CA's .48 housing and make it fit on that turbo. Now you will have the best of both worlds with a tad bit more top end loss.

Dee

[Daemos]

Don't think about the .86 A/R. Your CA doesn't flow enough CFM like the SR does, so your response times will be much later in the RPM band. You will have top end, but at the expense of bottom end response loss. The .64 might be your best recourse. you'll lose some power on the top end compared to .86 A/R, but you will spool much quicker. Would be even sweeter if you could machine the CA's .48 housing and make it fit on that turbo. Now you will have the best of both worlds with a tad bit more top end loss.

Dee

Any other turbos you can recommend that (may be more expensive...but it's gonna be my fun car )might give up some low end, but gained in top end power?

Basically I'm looking for something that hits full spool by 3500 rpm, and something that can hold strong til 8000 rpm....

[boost_boy]

Quote »Any other turbos you can recommend that[/quote] I can't really offer a suggestion without asking you to at least have a T3 flange welded to your existing manifold. The other choices are good, but that 0.86 A/R is not good for our CA motor.

Dee

[soflajdm]

like i said... check this out

http://linux.forcedperformance...e=DSM

[boost_boy]

Seems to support alot of DSM stuff. For flexibility and cost effectiveness a t3/t4 would be a good alternative.

Dee

[CA19DET]

S15 T28 is my suggestion, beats all the others on price and it works awsome.. if money isnt a problem, then the GT28RS is a good option also...

[quest]

I don't buy any of this disco potatoe crap. All I hear is "noise" and no numbers to back it up. I remember gettin into a 'lil discussion' with Mike Kojima on the se-r forums over this - I don't accept a turbos 'superiority' just because the status quo says so... you'd better show me the money.I'll say it again. Best performing t28 I've seen is the FP big28. For the money, hands down winner. I've seen at least two folks say their s15 turbo was no comparison to the big28 bolted on the same car/ same mods.Some on freshalloy tried to 'talk down' the big28. When I asked to show a better performing car with *any* GT small frame turbo.... guess what? Not one response. Seems like folks get caught up on boasting high hp figures and pay no attention to torque. I always do.'Tuners' throw cams, intake manifolds, etc at sr20s with these GT turbos trying to hit the magical 400whp mark. What happens to the torque ? It drops significantly. Put on 0.86 housing and you end up with an expen$ive turbo that will get spanked by a $600 t3/t4, that even spools quicker (good mani and size it right).Fp big28 (on sr t25 core) has put down 325whp/ 335wtq on a stock sr20. No cams, no header, no intake. Did it on a conservative tune jwt ecu too, so you know the turbo has more in it. Full weight hatch ran 12.2 @121mph, 19psi, pump gas!. With a 5hitty 60ft and drag radials that broke traction and went sideways when the boost hit - thats torque! Thats an 11sec capable turbo folks.I bought an sr t25 from this same guy. That big28 went on to make 341whp and 374wtq! on another stock sr20, with better tuning. Almost identical numbers to this dsm.... very impressive imo.http://www.wincom.net/trog/car.html I think FP even running a $599 special currently. Hit em up. They know their turbos, no question. I think they clip the turbine wheel, so u can ask about that if u wanna trade it for more midrange response on the ca18. Somehow, I always suspected that FP used 18G wheels in these things.

[boost_boy]

The mentioning of a .86 housing on a CA18 just cracks me up. Quest, preach on "Poppa". I don't know much about the FP28, but the S15 unit sure as hell won't be on my list of power houses. I've driven an S13 with an S15 swap and the turbo seemed no better than my tricked-out T25 with T3 wheels.

Dee

[Daemos]

How's the responsiveness of the FPbig28? Remember I'm also looking for responsiveness as well as top end.

if I can't find one, I might need to talk to boost_boy about t3/t4 turbo selections, and I'll need to see where I would beable to custom frabicate a turbo manifold for that.

[Def]

FP Big28's absolutely DIE on the topend. They make decent torque, but don't even spool up all that quickly due to the bigger wheels in the small housing lowering the efficiency. These bigger wheels just seem to give up the ghost on the topend, with power peaking in the 5.5-6k RPM range on SR's.

The S15 turbo isn't a huge jump over an SR T25, but it definitely spools up quicker than a DP with equal mods. Look again at that SCC dyno, full boost after 4k RPM on a 2.0L SR. Your CA will definitely spool it later... I for one don't really like the compressor map for an SR, but it will honestly fit a CA better since it will be really efficient until maybe the last 500-1000 RPM before redline. With an SR it drops on efficiency as soon as you cross about 6k RPM, then at 7k RPM it basically falls off the map efficiency wise(below 60%) at 18psi of boost, 90% VE. 18psi of boost will most likely still put you slightly below 300rwhp with this turbo on an SR, and is probably the max you could really run on it. 16psi improves the efficiency things a tad, but not much, and you're looking at around 280rwhp from all the stuff I've seen on an SR(slightly less on a CA).

360rwhp of flow has been pushed out of a T28 0.64 A/R hotside with the GT series NS111 turbine wheel, so I don't see why almost EVERY Disco Potato sold has a 0.86 A/R turbine on it. You might gain a few HP over the smaller housing at the same boost level, but you're still dealing with relatively low power levels and putting up with a pretty large lag increase for that minor increase in power through less exhaust restriction. But I guess SCC has a hard-on for the turbo, so that's why everybody and their mom that doesn't want to actually learn about turbos and what makes them "good" for their application springs for without question.

A turbo that looks really hot to me is the GT2781R. It uses the 71mm 56trim compressor wheel from the GT35 with a T28 hotside in either 0.64 A/R or 0.86 A/R. I think the 0.64 A/R is still a good match for this turbo unless you really want to max the compressor out, in which case I'd say go straight to a GT2540R and be happy with your lag hog. I'd say the 0.64 A/R GT2781R could push 310-320rwhp on a CA with all the bolt-ons and the wick really turned up on the boost. Someone with an SR already made 317rwhp and about as much torque with one that had a 0.86 A/R housing and a stock O2 housing, stock intake mani, stock cams etc. I think he had to run about 19 psi to get that number though since his mostly stock setup was pretty restrictive.

If lag is a REALLY big concern, then you just aren't going to be able to have your cake and eat it too. Even a T3/T04E with a small hotside will have a slow spool if the compressor can push out 350-400rwhp.

[Daemos]

I'm looking for say full spool by about 3500 rpm and hold it til about 8000 rpm......and around 300-310whp...

Maybe less. IT also depends on the torque.

Trying to hit high 12s so I'd be VERY happy with a 12.999 time slip

But I'm looking for overhead power as I plan to do that with one sub in the back + a roll cage.

I'm not looking for a dyno queen. It's going to be a daily driver that I want response out of.

I was just looking at it SCC made their car have 280whp and they got into the high 12s...but that's on a SR20 which produces more torque than the CA18. So I am just assuming that I would require more power (Since hp is a function of torque) to get that 12.999 timeslip.

Def: as for that GT2781R where could I find more info about that turbo? and how laggy is it really? As for the DP with the .64a/r and the effiency what redline are you using as a guide? the stock 7500 or what some people want to use @ 8000 rpm (which COULD be my goal)

[mbmbmb23]

HKS GT2510??

I'm looking for say full spool by about 3500 rpm and hold it til about 8000 rpm......and around 300-310whp...

Maybe less. IT also depends on the torque.

Trying to hit high 12s so I'd be VERY happy with a 12.999 time slip

But I'm looking for overhead power as I plan to do that with one sub in the back + a roll cage.

I'm not looking for a dyno queen. It's going to be a daily driver that I want response out of.

[Def]

For airflow I used a 2.0L engine with a 90% VE(typical of a modded engine, maybe a bit conservative on how much it will be ingesting, so lower efficiency numbers) and a 7500RPM redline. So a 1.8L engine would take in even less air, thus making something smaller be more efficient.

I seriously doubt a CA will ever full spool a GT2781R by 3.5k RPM. I think an SR would do it around 4k RPM or maybe a hair before with the 0.64 A/R turbine. Add at least a few hundred RPM to that for a CA.

The 0.64 A/R GT28RS sounds like a good candidate for you, but I'd still expect full spool around 4k RPM. Should be able to push in the 280-290rwhp range with lots of supporting mods and high boost. I really don't think the Disco Potato will push much more power than an S15 turbo though... so if you might be happy with a hair less power then you could always save yourself a few hundred bucks.

[RMiller]

I bought a GTiR turbo. The compressor flows 33 lbs/min, .86 a/r turbine side and the compressor is a t3 cover. It seems like I'll get full boost from 3500-4000, I'm hoping for more like 3500. GTRS flows 35 lbs/min, so 300 whp should be possible.

If you just want to run 12's and have a responsive turbo, get a t25 or s14 t28. T25 will give you ~230 whp and probably your 12.99, and t28 will give you another 50 and lower 12's. Either one will be good for what you want. I've driven an sr powered s13 w/ and s14 t28 w/ about 250 whp and the thing was scary fast. I don't know what the car would run in the quarter, but I normally drive a 2000 mustang gt which supposedly runs [email protected] and the s13 seemed infinitely faster.

If you want to spend more money, get a 2530 over a 2510, 2540 or 2540r. 2530 would be my turbo of choice if money was not an issue.

[quest]

>>"FP Big28's absolutely DIE on the topend"

hmmm.... lemme see now. Full wt s13 hatch traps 12Xmph, with traction issues and a less than stellar tune. Turbo has no prob holding 23psi to redline, and you say it "dies on top". Where do you run at, bonnevile?

What then are you baseing this on ? Please share this 'better' turbo with us. Forget compressor maps and dyno charts - we don't drive em. Lets see "real world" numbers from a car with your turbo choice.

Don't waste your time trying to find a better performing $600 bolt-on turbo.... I bet the big28 will wax it.

[Daemos]

Well then, I wish I had copied everything down...before this place was rudly hacked :/

Anyways, I'll list off things again:I know that turbos for Autox and Drag would be totally diffrent. And that high boost = no traction for autox, but wouldn't that be more of an unskilled driver than anything else?

I'm looking for a car to have the ability to do both (very high 12s and good autox) as long as the driver is good.

I'm looking for a turbo with a thick powerband (although I might need to drive a stock 180SX to determine what I REALLY want to improve) so I can have a good powerband for autox.

But Saying that I also wonder how Stock S2000s do so well since their powerband is really only good from 6000-9000 rpm which is only 3K rpm...

Anyways there was something about T3/04 in there I was reading at work, but it was all lost and I didn't really remember what was said, so yea

then float_6969 whom is a fellow autoxer also had alot of advice and tips, which I totally missed on (stupid hackers)

[Daemos]

One last question, can the T3/04 turbos come in BB form? with a .42 exhaust + .6 turbine, with a BB I'm sure that would be virtually lagless

I'm looking for a turbo that hits full spool by ~3500 rpm, but has very little lag, ie hits boost almost instantly...

And where would you beable to find a good T3 manifold for the CA as well a place to build the turbo to your specs?

[Def]

I think you'd be pretty happy with a max'd out SR T25 or T28 and a lightweight car for autocross. Just my take on it after driving around with a mostly stock SR.

If you are on a slower course with anything bigger you WILL lose significant amounts of time on something like a hairpin waiting for the boost to build back up. S2000's as an example are really really strong in BStock on fast flowing courses, but put a hairpin or tight slalom section with a straight past it and my times with a mostly stock BMW E36 M3 would get very close to guys that would normally kick my arse with much more prepped cars.

I was talking to a guy building an S13 SR powered car to take to the Nationals in Street Mod. National level courses are very fast and flowing, so he was going to shoot for alot of HP(350rwhp or so I think) and just deal with a little lag. The typical autocross course is just not condusive to this.

As for the FP Big28 having "results" - sure, it can make power, I never said it didn't. Yet it is really a turbo only suited for drag racing/cheap bolt-on street turbo in my opinion. The efficiency of it stinks at high RPM, shown by the rapid power drop-off on dynos(which *ARE* very useful, as are compressor maps and the idea of efficiency). It'd be really frustrating to have a turbo that had so much midrange torque that it was all throttle modulation then once it hooked your torque just rolled off quick and you had to short shift the gear. It makes enough power to throw a light car down the track pretty quickly, but I don't like the power delivery or how much heat it is bound to generate with those big wheels in the small housings.

BTW - if you want a full interior car with all the luxury items and sound system etc. then you are going to need a good deal more power than a light weight car to run 12's. So keep that in mind. Every bit of weight you save on the car will get you that much closer to your ultimate straightline goal without increasing lag or really costing all that much.

[Daemos]

Seats will probally be ditched out for recaros (REAL rocaros, no ebay recaros for me) rear seats removed, 1 12" JL sub, roll cage. And compoents all the way around.

Interior re-upholstered....(make it all black) then just have an aluminum dash kit.

So technically I don't think I'd be adding too much weight onto the car...not too sure....but that's why I wanted more power I need to counterbalance weight somehow

I've been searching for more results about the T3/04B with a .4 exhaust and the .6 turbine...and haven't come up with enough info interms of when boost starts to kick in, and when max boost hits...as well as the question can you get it in ball bearing form? I wouldn't mind paying extra money to get ball bearing (which would help reduce lag) So in that case, it would seem (if this turbo works out the way I *think it should (it's 2:30 am here...hahaa so brain = tired)) I would have a low-lag turbo that would beable to pull from low rpms all the way to redline...(which would be ~7500-8000 rpm)

[RMiller]

I really think you should get some form of a t28. They spool really fast; they make more than enough power to get your high 12's. If you don't mind spending more money, then get an hks 2530. It will be awesome for autocross and I imagine you could get around 320+ whp. Both of these turbos will meet your needs. I don't see any reason to consider a t3 turbine if your goals include instant response and high 12 sec. timeslips, unless you don't mind some extra work.

[Daemos]

I really think you should get some form of a t28. They spool really fast; they make more than enough power to get your high 12's. If you don't mind spending more money, then get an hks 2530. It will be awesome for autocross and I imagine you could get around 320+ whp. Both of these turbos will meet your needs. I don't see any reason to consider a t3 turbine if your goals include instant response and high 12 sec. timeslips, unless you don't mind some extra work.

Remember I'm also looking for KILLER top end. Where T2x turbos tend to die off top end...T3/04s keep pulling.

So if I can find a T3/04 Turbo that starts boosting around 3000 rpm (with ball bearing) and can hold it's own til ~7500 (so I'm only 500 away from redline) I don't think there should be any problems

I don't mind spending extra money, all it means I just gotta save more