Limiting Factors on max boost for stock CA?

[Porschephile]

Well, I've researched for awhile and haven't found much in the way of specific details. My question is, can anyone tell me what about a stock CA (ecu, maf, injectors, etc) limits running more boost the most? I have the following bolt-ons:

-cone air intake-3" Greddy Exhaust-SR T25-MBC

The rest is all stock. I remember someone mentioning that 11-12psi is about the max you can run on a stock CA before seeing any problems. Is this true? As far as I can tell, the stock turbo and MAF seem to be severe limiting factors but I can't think of much else that could really hold me back from running as much as 1bar at the most. I would think the stock injectors, fuel pump, etc combined with an SR T25 and 75mm MAF should make that possible.

I have an extra 3rd gen Maxima MAF laying around, and I am going to reprogram the ECU so that I can use it. It is 75mm in inner diameter, and it's so similar to an Rb25 MAF that I bet they are basically the same. Either way, it is good for ~300hp, and anything seems to be much larger compared to the stock MAF!

So am I right? Are the stock MAF and t25 what prevent you from running more than ~12psi safely, or are there other things?

[Nismo1182]

The stock sidemount is crap. Take my word for it since I had to replace my headgasket for pushing 15-17 psi on stock MAF, SR sidemount, stock CA turbo, stock injectors, Mines chipped ECU,walbro 255, stock sr downpipe, 3" test pipe, 3" cat back, kn filter, MBC.

With my new mods and timing backed down, I push 15-14 without a peep from the motor but I run 10 daily.

New mods are,1G DSM sidemount, AFC2, S14 KA MAF, SR T25 turbo.

On everything stock, I wouldnt push more than 12.

[Bizz]

I'd go with bigger injectors before 12+ psi . I don't know how accurate this little program is http://www.iroczone.com/calcs/injectorsize.htm but it says 512cc for a 250hp turbo motor. Is 250 around what you think you would get outta a 12 psi on a t25?

[Nismo1182]

Not at 12 and not on the stock CA T25.

My friend SR20 did 250 something with the stock turbo at 15 psi and stock 370 injectors. CA also has 370 injectors.

But anything over 10 psi on a big turbo, larger injectors are needed.

[CA19DET]

550cc injectors should be good for about 350whp

[r34 gtr]

yeah, 512 for 250hp is very overkill, you would have to correct for the bigger injectors like crazy because you would be running almost half as rich as me! (dont ask why, i dont know whats wrong with it). the side mount intercooler is probably the most limiting factor. you can probably push 14psi on the sr t25 all day long on just a front mount without even the hint of a problem. that should make you a bit over 200whp. 220 maybe? anyway, good luck with it.

- tim

[PacManVR4]

I dont think a t 25 if effecent up. Wouldent it turn into a hairdryer over 14 or so PSI?

[r34 gtr]

the t25s lose efficiency after about 15psi. yes, they suck big time.

- tim

[Nismo1182]

The CA one sucks worse since its smaller.

[ants13]

T25 on a ca will hit 15psi easy. thats when you hit fuel cut ( at least it is on the UK spec) They aint efficient at that pressure but there are cars over here that are mapped with them to peak at 18psi. best bet is a T28 from an s14 SR, Not from s13 sr. Also dunno how cheap it would be for you guys but a lot of the Uk peeps use a 2nd saab or volvo FMIC. We get them for about $80 and just have to pick up the pipe work. That totals about $220 for a complete FMIC kit.

BTW hows she runnin now?

If you need any help feel free to email me.

[Porschephile]

Hi Anthony! Good to hear from you again. The CA is running GREAT. It's running smoothly and feels like it's making decent power. Man, I can't get enough of this CA! After the swap I kept bothering my brother and trying to get him to sell me the car! Are you coming back to TX any time soon?

[ants13]

I'm hoping to get back to TX some time this year probbly june/july but At the min I'm building my s13 so it's takin all of my money and time!! Good to hear that the CA is runnin good. Hope your brother sells you it!

[s13ofdoom]

word of advice running max psi on any stock motor isn't a good idea (protect your motor try not to kill it )

[float_6969]

Stock CA T25 = stock boost. I wouldn't dare turn it up. Maybe with a good FMIC and I still wouldn't go past 10. I don't trust them. If you want to turn it up, get a decent turbo.

[ants13]

perhaps not the best idea to turn them up, but plenty pf peeps do run them at 13-15psi without problems. When it does let go just upgrade to an s14 t28 or s15 t28 or whatever you decide on. they can be run at more than stock boost tho.

[s13ofdoom]

well yeah u can run them safely past stock boost im just sayin i wouldn't try to test the limits then your just running the risk of damaging stuff (noo need to kill a turbo ), but feel free to if u want.

[ants13]

Soz but all i meant was that my CA will generally run at 13psi. (Stock sould be about 9) And it will hit 15psi as soon as the temps drop. Only engine mod on mine is a Nur spec R. Everything else is completly stock ( mainly coz i aint got round to doin it yet LOL) But i do understand your point about not killin the tubby.

But back to the topic in hand, I think the best way for Porschephile to go forward would be aeither a t28 (S14 or S15) and a FMIC, After thet fuel pump and management would be needed IMO.

HTH

[float_6969]

^^exactly^^