when do stock turbos typically reach

peak boost for a manual/auto? looked and looked and can't get an answer.

peak boost vs rpm answer would be nice!
i.e. 10psi @ 700rpm (lol)

what is stock boost 8 or 10psi?

thanks

 

I thought it was 9psi and no idea when it peaks

 

hmm stock boost is 9psi....7psi when in saftey boost!!! this is correct yes?

 

correctomondo artin

 

thanks for the responses but any clue on when the 9psi

is achieved wrt rpm?
thanks

 

8.5psi

9psi is reached at about 2,500rpm in stock form then it gradually drops to 8 by 4-5,000 the to 7 by 8,000
(average of numerous individually computer maping sessions in real time driving + temps, and we didn't get caught!)

so to average it out, taking into account and assuming you have standard extractors, intake and coolers. the average is 8.5psi.

stock turbos hit max shaft speed around 16-19 psi but going this high is NOT recomended if you value your wallet content.

tune both your turbos to run 12-12.5 psi as this is what your injectors can handle. remember to tune your timing to suit aswell.

 

Quick take off in first gear probly about 2500-3000 at the very most? Hardly remember anymore, had bloody code 34 for that long now!

 

thanks for the response, I'm trying to diagnose a

problem with my setup as opposed to alter it.

I seem to be running:
8@3650rpm
8.5@3700rpm
12.5@4200rpm

I have all the bits + pieces to support the above,

• 3" exhaust + dump pipes + highflow cats
• boost controller
• remapped ecu
• ud pulley
• lightened fly wheel
• lightened tail shaft lol
• ect ect

so based on the info you provided + Oz300's dyno graph it would appear my turbos are working much harder than required. So based on this it supports my other findings (can't hold pressure for boost leak test - thought this may have been attributed to me as opposed to any real problem) that I do infact have a substantial boost leak that is affecting performance.

once again thanks

 

You definately have a problem......

firstly you should fix the boostleak and then you can determine if you have other problems as well.

When I have my EBC set on "low", at 3500rpm the boost hits 10psi and sits there all the way to the rev limiter

My "other" zed hits 9psi at 3800rpm but they're not stock hairdriers

 

mafi has been running 1bar for some time now on stock injectors....dont know if he is overdoing his injectors or anything else or how long the parts have to live, but its still going strong...

 

you can reach 17psi...

easily on Stock turbos and Stock injectors.
As long as your fuel map and timing can support it. upgraded I/C's will aid this.

If you've had a remap, you would probably have more chance of reaching this than stock. Even with no I/C upgrades you should be able to reach 13-14psi easily.

Check your boost leaks. and ideally you should be doing this whilst on a dyno.

cheers,
Ben

 

injectors are fine @ 15psi.. cold night, 16psi and 7300rpm you will be in trouble

 

remember stock turbos effiency range is over at 16 psi, so not really any difference between 16psi to 16+psi.

also having a FMIC will increase lag but allow to run more boost.

 

also if you run 16 psi often your exhaust wheels will fail and fall off.

 

That is nonsense!

My car has been running 16-18psi as a daily driver for the past 6 1/2 years. The wheels haven't fallen off, but my posts have been VTD'd for saying so. Sorry ladies but those are the facts.

 

Seconded Lloyd...

**about the boost, not your VTD's** lol

These are pretty tough engines, you don't need to baby them toooo much.

I've been running high boost on mine like Chili has been - and still as healthy as it did when it drove out of Nissan in 1990! I've only recently turned my boost down from 17psi to 14psi due to my new U/D pulley which lets me achieve the same power as i've always been getting, except now only at 14psi.

Here's the testimonial -- just have a look around at the amount of members running 15-17psi on their stock turbos & injectors.
- Trust me there are quite a few. - just make sure you're not leaning out, as that's the main killer! This is why i suggest you do this on a dyno!

 

Probably not as many now after all the FMIC and Sard 650 Group buys but i see your point

 

I'm guessing that there's not a big power increase as measured at high rpm's when you're using stock turbo's, stock injectors and stock IC's when you increase boost from 15psi to 18 psi

the reason that i say this, is because injectors can't really flow much more, turbo is heating the air up, etc

fair assumption?

 

heh dotn forget about me guys

BEen running 1.32-1.38psi on stock inj/turbos. Been runnign fine for 2 months now. Its my every day car. Dont thrash it really unless needed!

But yeah. thats like 18-22 psi! No ping/detonation.

 

Icer i hope your

af's and timeing maps are up to it, but i reckon @ 18-22psi your pushing your luck.