Noob Question: Boost

[AadosX]

Ok this is very noob and I'm posting it really quick before I leave my friends house (who has the internet, and I don't) so I don't have time to search now but thought someone would just generally shed some light on this issue. I'm about to install my SR into my S14 and was wondering about the boost level. My goal is 250 rwhp, I've seen that supposidly the turbo is reliable to 14-15 PSI. Well, what exactly IS the reason to not use 14 PSI all the time? I mean, why not? Will it affect the engine or just mess up the turbo?, IF it's bad for it at all. I may get a new turbo later on so if it's just a little bad for the turbo, but doesn't hurt the engine, then I'll just do it. I'll have an FMIC and an EBC btw. Lastly, if it's not a good idea to run high boost all the time, could I just use the EBC to keep the boost at around 9 for daily use, then when I'm racing turn it up to around 13-14 for the day?

Thanks, and sorry for the noob question!

:bowdown: :bow:

[DuffMan]

If its an S13 motor, than 14psi is out of the turbo's efficiency range, and it is spinning at rediculously high rpms. That being said, it might break and it might not. It depends on how worn it is, and luck.

For an S14 motor 14psi is fine for the turbo, but you're reaching the limit of the stock injectors.

[Steeles]

I run 14psi all the time.. its all dependent on what shape your turbo is in. some stock T25s are still making power at 16psi. (with 12:1 A/F ratio :eek: ) every car is different get it running get to a wideband and a dyno and see what yours will do. THEN start modding

[AadosX]

If I got a new bigger turbo, would I have to replace the injectors anyways?

[Steeles]

have too? no... but one of two things would happen.

Option A; you'd be stuck running very low boost in order to avoid option B

option B; BOOM

so yeah upgrade turbo = more air. add more air your car is not happy. to keep car happy add fuel proportional to air (hence Air Fuel Ratios importence) so add air + fuel = happy motor

[AadosX]

Oh I see, thanks a ton. So do you think a SAFC would be a wise mod if I'm running 14 psi on the stock turbo? Howbout on the new turbo? I'm assuming yes to both, just making sure.

[uiuc240]

You shouldn't outflow the stock injectors or Mass Air Flow Sensor (MAFS) with the stock turbo at 14 psi. You might have to turn boost down on hot days, as the air from the turbo will be really hot and probably encourage detonation. But on cool days, you should be able to run 14 psi on the stock T25 with stock parts.

The S-AFC will not be able to take you much further than that because it can't make the injectors flow MORE than their max flow...370cc/min (you can richen a mixture, but only to the point of static flow). The only way to up that number would be to increase base fuel pressure, which can be somewhat risky.

However, the S-AFC will pair very nicely with a set of 550cc/min injectors (~$400-500) and a Z32 MAFS, giving you the ability to tune all the way to about 375hp. Obviously a T25 or T28 are never going to approach this hp level...you will need a bigger turbo.

Any other questions?

Eric

[AadosX]

Amazing, thank you immensly. Yeah, I just got off the phone with Augusta Customs in GA, GREAT people. The guy knew what he was talking about and talked to me for nearly an hour. He also suggested the Nismo 550cc Injectors, but didn't say anything about the MAF so I'll ask him. I think I'm going to end up getting a bigger turbo, but for now I'm going to just run 14 psi and see what happens. Ahh I can't wait!!!:D

[Steeles]

uiuc240 - when I hooked up my SAFC its reading my stock mafs at 100% by the time i hit 6000RPM (got the 300zx in the back seat now though, just waiting on a warm day)

[uiuc240]

Steeles...do you mean at 14 psi?

That could be possible. You're not making any more boost at 6000 rpm than you are at 7000 rpm, so it shouldn't be a problem. In fact, you're making less. Also, a 100% reading isn't exactly bad, either. That just means that the ECU is sending a signal to the injectors to run at full flow at that time. As long as your injectors can pump enough fuel, it should all be kosher.

Personally, I wouldn't run things this way...but technically, it should work fine. Get that Z MAF on there, yo! :cool:

Eric

[Slow SR20]

yeah with the extra air you gotta measure it so get Z32 MAf
, 550cc injectors, turbo upgrade, now manage that with some source of tuning. I am going with a RE-Flash from secret services.

[Steeles]

Originally posted by uiuc240
Steeles...do you mean at 14 psi?

That could be possible. You're not making any more boost at 6000 rpm than you are at 7000 rpm, so it shouldn't be a problem. In fact, you're making less. Also, a 100% reading isn't exactly bad, either. That just means that the ECU is sending a signal to the injectors to run at full flow at that time. As long as your injectors can pump enough fuel, it should all be kosher.

Personally, I wouldn't run things this way...but technically, it should work fine. Get that Z MAF on there, yo! :cool:

Eric

true enough but im reading it WAAAAY before 6000. but i've also got my 16g sitting here waiting to spit 21psi through the engine when I get injectors that can keep up :)

[uiuc240]

Originally posted by Steeles
true enough but im reading it WAAAAY before 6000. but i've also got my 16g sitting here waiting to spit 21psi through the engine when I get injectors that can keep up :)

Is it pinging?

Then don't worry about it :D ;)

That 16g is going to make your car FASSSSSSSSST. When does that go on?

E

[DuffMan]

A 16g is an interesting choice to go with. Hardly an upgrade, for all the trouble of switching to a mitsushi flange, and compatable 02 extension.

Is it a hold over until you get a better mitsubishi style turbo?

[Steeles]

uiuc - when I get the ignition problem sorted out I'll let ya know lol. (missing trying to hold a steady RPM under boost above 4K) and as soon as thats done and I get injectors that bish is going on. :) a friend had a first gen eclipse with some work done too it (ran 12.1 in the quarter) with a 16g on it so Im really excited to see what it does :) i figure some cams and tuning should get me just under 350 or so.

Duffman - not a true 16g. 16g compressor in a bored out T25 housing. clipped exhaust wheel all balanced and blueprinted. opened up to a 30mm wastegate port. she'll bolt right on in the stock place. I'll throw my HKS actuator on it and a boost control of some kind. may go manual till I get a fancy pants EBC. leaning towards the new HKS

[DuffMan]

Ah, thats cool then. If it fits in a modded t25 housing. I wonder if I could do that with a ball bearing 18g.

[Steeles]

now that would be intresting... although I'd imagine a bigger exhaust would be needed. mmmm ball bearing....

hehe I also got Taka motorsports SS oil and coolant lines for this puppy when It goes on. im thinking about getting a SS manifold too like the project siliva or someother budget manifold... but I'm weighing those against a nice set of cams. I want to flatten the torque curve. I cant decide on 256in 264ex 264in and ex or 264in 272ex. :) ahhh decisions decisions...

[Phlip]

Originally posted by Steeles
got the 300zx in the back seat now though, just waiting on a warm day)
Brandon... You rate bastard... IT'S 62 DEGREES IN A NORTH CAROLINA JANUARY, GET YOUR LAZY ASS TO THE SHOP!!!

[Steeles]

What shop?!?!?!?! didnt you hear MBH is gone lol. I dunno whats thte deal on the new shop or whatever. Heydens car is at his place and well fawk i dunno whats up. I'm gonna check it this weekend. I'll pull it into the warehouse here and see what I can do. then take it to ATL and let Russ go crazy later :)

[DuffMan]

they both use a td-05 exhaust, so i think it would be okay. Maybe if not a 18g one of the mitsubishi-style IHI turbos. New ball bearing turbos for like $800 bucks. Did you get your t25 exhaust housing done somewhere, and if so, how much was it?

[Steeles]

BNR supercars in Alabama did all the work. all this from a stock T25. Price was... in the 500 range.. cant remember exactly. about what you'd pay for a big 28 upgrade from forced performance.

[DoriftoSlut]

Its all about keeping the fuel pump open to its highest flow, running FMIC, NO BOV!!!, EBC and .9~1.0 bar on stock T25.

I would do that but im a pussy. I know of some "teams" that do that in Japan. Fixmer is friends with them. He says they make around 250-270ps and are some of the best drifters he has ever seen.:drool:

[sykikchimp]

Originally posted by Steeles
BNR supercars in Alabama did all the work. all this from a stock T25. Price was... in the 500 range.. cant remember exactly. about what you'd pay for a big 28 upgrade from forced performance.

About the same performance as the Big 28? Seems maybe it even outperforms it a bit?

[Steeles]

Originally posted by DoriftoSlut
Its all about keeping the fuel pump open to its highest flow, running FMIC, NO BOV!!!, EBC and .9~1.0 bar on stock T25.

I would do that but im a pussy. I know of some "teams" that do that in Japan. Fixmer is friends with them. He says they make around 250-270ps and are some of the best drifters he has ever seen.:drool:

hahah no gotta go top mount!! lol Im still thinking about doing that. at 14psi it made 240hp and 239lbs/ft (I wanna know what kinda difference the new exhaust made though that pull was with the N1 Dual still on. not expecting a huge change but curious)

About the same performance as the Big 28? Seems maybe it even outperforms it a bit?

hehe dunno... find me a big28 and I'll compare lol. but yeah should be around the same HP wise. Looking to pull 320ish at around 20psi. maybe more cause of the football and possibly a new ex mani, IM waiting to hear from Planb about how those SS autochrome ones are holding up. cause I can pop up to raliegh and snag one of those :) but I like how the 16g pulled on the dsm

[AadosX]

Steeles, you in AL? I'm in Auburn/Birmingham... I get my work done in Augusta, GA.

[Steeles]

nope Im in North Carolina. one of the guys that works at BNR is on the 240 over atlanta list. when I mentioned wanting something done to the turbo he offered.