Upgrading the turbo on the SR20DET

[S13 King]

I'm still in the process of learning compressor wheel trims and the diffrent affects, etc. I was reading a post on another forum and they were talking about rebuilding a T25 turbo with T28 internals. My question is, rebuilding the turbo like this, what is the advantage, and what is the max boost and hp that can be expected from this?For my blacktop SR20DET I'd like to see about 400hp daily driven (and I mean it) I do know this is going to require extensive work but i'll get there shortly.

Thanks for any answers.

[msaskin]

The most power you're ever going to get out of any T28 variant is going to be about 300 or so at the wheels, and that's with a bunch of other supporting mods.

If you're looking at a reliable (hahaha!) 400+ rwhp, you're going to want to probably build the motor, and you'll need to use one of the following turbos:If you want to stick with a bottom mount (stock style) turbo, your only real hope is a GT25R or bigger. Even the GT25R may be a bit small, as the most power I've seen someone put down with one of those is 390rwhp, and I believe that was with cams, an intake manifold, etc. I feel your best bet for those power goals is a top-mount turbo setup. Check out the enjuku racing one.

I also feel (no offense) that you need to do some serious reading. Judging by your basic questions (why am I hitting fuel cut, is there a high performance o2 sensor, etc.) you need to have a better understanding of how your car works before you start trying to wring out that much power

~matt

[S13 King]

True I agree I am new to this motor, I came off the KA24DET and started knowing stuff from hondas I hate to say but Since I've moved to Nissan I have gone back. Yes I'm still reading and learning. Right now I'm just looking at the longevity (sp) or my SR. However I'm also planning for the future of my SR.

Thanks for your help and advice though. I'm trying to find as much CORRECT tech advice and info as I can.

[pampadori]

yeah for 400whp you need something large. its going to be laggy and all power will be 4250rpm and higher. you will need large injectors and a way to run them, ie. jwt ecu, standalone....s-afc is going to have trouble controlling the injectors you need for 400hp. Shaun

[dj_lennon_franz]

2 words

T78 kit

400rwhp will require quite a bit of time money and effort...and thats ALOT of power to make on a SR...what do you plan on applying this kinda power to??? (ie:drag racing/road racing/drifting???)

[msaskin]

2 words

T78 kit

400rwhp will require quite a bit of time money and effort...and thats ALOT of power to make on a SR...what do you plan on applying this kinda power to??? (ie:drag racing/road racing/drifting???)

I'm gonna assume drag racing. That much power in a 240sx really isn't good for much else (aside from the pro drifters who run like, 450hp, but that's insane).

Hell, my 350hp goal is going to be a bit past normal for road racing, but some headwork can take care of that

~matt

[NY S13 SR]

Power Enterprise 1820SP, JIC manifold, HKS cams, Z32 MAF, JWT ECU tune and NISMO 740cc injectors and you are there._________________Jeff Holdenheavythrottle.com

[Def]

Do realize that there is probably going to be very little torque below 4k RPM with a 400+rwhp setup. A GT2540R 0.86 A/R turbine is probably not going to get you to the "magic" number, but will be the smallest thing that could possibly get you there. Needless to say, why would you want a powerband like that on a daily driver?

If you REALLY want that much power - I'd just go with a T3/T04E top mount.

[DriftS14]

Power Enterprise 1820SP, JIC manifold, HKS cams, Z32 MAF, JWT ECU tune and NISMO 740cc injectors and you are there._________________Jeff Holdenheavythrottle.com

That's good to know. How far do you think my 550's will take me? My setup is almost the same save for the JIC mani, JWT ecu and cams.

[pampadori]

550's can do around 350whp. a little more if you stretch em out.Shaun

[S13 King]

Well I'm changed my mind do to some math,lol....."Its great to learn cause Knowlage is power"..

As i'm sure most of you know the 240S S13 chassis is the lightest of the 240s. So I'm thinking that if I can make 375hp to the wheels would do what I'm planning on doing.

I'm building the car as daily driver, road racer, track every now and then, drifting rarely. I hate drag racing so boring so little time for so much money.

[msaskin]

Honestly, 375rwhp is A LOT for road racing/open track events. Any turbo that makes that much power won't be making any power until at least 4000rpm, which is a bit on the high side for road racing.

Granted, I'm aiming for 350rwhp and I pretty much only road race/open track the car. It's kind of a do as I say, not as I do thing. I also plan on drag racing, and I like having a car with some top-end (compared to my old galant vr-4, which made all it's power below 100mph or so).

I would suggest if you plan on going to open track events and not drag racing, go with a GT28RS ("disco potato") or a Ball bearing T28. Those will both let you hit 300rwhp (more with the GT28RS) while at the same time giving you AWESOME spool times, and great boost recovery after shifting.

~matt

[Def]

Quote »Granted, I'm aiming for 350rwhp and I pretty much only road race/open track the car.[/quote]That's my aim as well. Although I'm not really too keen on the GT28RS for my goals... I think that I'd eventually get kinda bored of the power. Ya know, when you only "kinda" flyby E46 M3's at full song on the back straight, it just isn't enough sometimes.

[Def]

BTW - 375rwhp is right up a GT2540R's alley. Go with the 0.86 A/R hotside and you might push a bit more out of it if you go with cams and an intake manifold. It will be a little laggy for road course use, so you'll have to be good at anticipating the power delivery and trying to keep your revs up in some corners but I'd say it's doable.

I'd probably say a turbo making only 20-40rwhp less would be almost, if not just as fast around a track without huge straights just due to the powerband and response differences. Something to think about...

[msaskin]

Quite true Def. I just like having the extra power to play with

The one thing I'm doing differently than anyone else running a GT25 thus-far is using an AEM as opposed to just ROM tunes or piggybacks. Hopefully that'll let me tweak every last bit of power out of the car. Right now I'm just going to be using the smaller hotside and see how it goes. Down the road will come some light headwork/head gasket/intake manifold, and maybe cams.

I would agree on not being too keen on the GT28RS/GT2871R. They both offer awesome spool, but the most I've seen a car put down with a GT28RS was Stephan Papadakis' (yeah, the AEM drag racer) drift car at an event here in Vegas. He said he was putting out 317rwhp with a 28RS and 272 cams, and you have to remember his car was running an AEM and tuned by possibly the best AEM Tuners in the country (the AEM engineers )

~matt

[Def]

The GT2871R looks like a pretty sweet turbo to me though. Not quite as beast as the GT2540R, but should be capable of 330-350rwhp maxed out.

I'm thinking the average GT28RS output will be in the 300ish rwhp range depending on supporting mods. 317rwhp probably has it putting out TONS of heat compared to a more efficient turbo at that power level.

[pampadori]

we got 320whp with a gt2871r (jgybb37) on a g20 with a det at 17psi. the compressor can flow enough air for 400whp. with some cams, a good tune and 20-22psi i think its possible.Shaun

[Def]

Is this 400whp based on real world results or theoretical? I looked at a compressor map, and at 20psi it would get inefficient on an SR above about 6.5k RPM pretty quickly. I could see 350-360rwhp, but 400rwhp sounds like it's tough for a larger GT2540R with a 0.86 A/R turbine.

[blink3180]

couldnt you just put a t04e, injectors, new intake and exhust manifold, and do alot head work and get the 400 hp no prob?

[msaskin]

couldnt you just put a t04e, injectors, new intake and exhust manifold, and do alot head work and get the 400 hp no prob?

You're ignoring tuning, the custom work needed for a top-mount turbo (custom downpipe/o2 housing, intercooler piping, etc.).

It's a lot easier said than done.

~matt

[Phax]

...Right now I'm just looking at the longevity (sp) or my SR. However I'm also planning for the future of my SR.

Thanks for your help and advice though.

Longevity and high boost levels do not go hand in hand. You really either get one or the other. If you want 400whp daily driven, look at a Supra, or maybe an RB26 powered 240. Those are the kind of engines with the displacement to put down 400whp at sane boost levels. To get 400whp out of 2.0 liters, you are going to need to run 20+ psi, and 20+ psi is not good for engine longevity, no matter how built your motor is.

[pampadori]

Is this 400whp based on real world results or theoretical? I looked at a compressor map, and at 20psi it would get inefficient on an SR above about 6.5k RPM pretty quickly. I could see 350-360rwhp, but 400rwhp sounds like it's tough for a larger GT2540R with a 0.86 A/R turbine.

garrett underrates their wheels. sometimes very much so. i've heard of a guy that had a -11 chra rated at 50lbs/min make 575whp stuffed in these same housings. so i wouldn't just assume the maps are in stone. people always make more power then what a turbo is rated for. not that that is how you should abuse a turbo, but many still do.Shaun

[S13 King]

well I was talking to my guys at SGP racing in houston and we've decided that the CTC Motorsports turbo kit is a good kit for what i'm shooting for.

[NY S13 SR]

From CTC Website:

"With stock injectors, a 300ZX fuel pump and absolutely no fuel control, the test car put down 340rwhp at just 11psi of boost. "

Stock injectors / MAF / ECU making 340rwhp? How's that done?

___________________Jeff Holdenhttp://www.heavythrottle.com

[msaskin]

FMU to bump up base fuel pressure to unsafe levels??

~matt

[NY S13 SR]

Even so, stock S13 SR MAF only supports 280-290 hp. Looks like a nice manifold though.

_________________Jeff Holdenhttp://www.heavythrottle.com

[DriftS14]

From CTC Website:

"With stock injectors, a 300ZX fuel pump and absolutely no fuel control, the test car put down 340rwhp at just 11psi of boost. "

Stock injectors / MAF / ECU making 340rwhp? How's that done?

___________________Jeff Holdenhttp://www.heavythrottle.com

Wow, that completely tosses everything I have ever learned about injector sizing versus power.

[msaskin]

Wow, that completely tosses everything I have ever learned about injector sizing versus power.

In what way? That it's unsafe to run that much power on those injectors, or that they somehow are able to do it?

My guess if they're truly on stock MAF/injectors is that they're unsafely bumping up fuel pressure to get the injectors to give more fuel (in which case they're asking for the injectors to just lock up on them), and possibly using a reed valve to bypass air around the MAF at WOT.

Look at these formulas:http://www.haltech.com/injformula.htm

These are the #'s that most go by for choosing injector size.

~matt

[DriftS14]

In what way? That it's unsafe to run that much power on those injectors, or that they somehow are able to do it?

My guess if they're truly on stock MAF/injectors is that they're unsafely bumping up fuel pressure to get the injectors to give more fuel (in which case they're asking for the injectors to just lock up on them), and possibly using a reed valve to bypass air around the MAF at WOT.

Look at these formulas:http://www.haltech.com/injformula.htm

These are the #'s that most go by for choosing injector size.

~matt

I think it's the "somehow it was done" part. It clearly states that no fuel control was used. But if fuel pressures were increased, perhaps enough to lock up the injectors like you said, wouldn't the injectors reach a maximum flow point eventually? 340 wheel horsepower would require 550cc injectors to flow at their best, I couldn't imagine what it would take from a 370.

[Def]

120+psi of fuel pressure would probably do the trick. You'd probably be luck to go more than a few months at that level before something bad happening to your injectors though.

Honda guys have pushed 250-270whp from their dinky 240cc injectors this way for a while, but it also isn't uncommon for injectors to get stuck open or closed and engines to die too...

FMU = bandaid fuel tuning solution

BTW = the injector just serves as a known restrictor valve that limits flow based on the pressure differential across it. Raise the pressure and you will always raise the flow(at least at the flowrates we're talking about here).