whats the deal with 20 PSI????????

[my98gsx]

I went to the track yesterday only to leave disapointed... after all of my hard work over the summer i was only able to squeeze out a 12.79 @ 106. @ 15lbs. The thing I do not get is Evo's have a 4G63- sure they have different computors, heads, transmissions, but when it comes down to it THE BLOCK IS A 4G63. I see evo owners running 24, 25, or even 30psi on a stock block! If this results in no engine damage then why are eclipse/talon drivers "limited" to the magic 20psi mark? - I got tuned last year and the shop refused to tune me over 20psi, and over the past few years turbo companys tell me the same thing- "keep it under 20!"

Heres the problem... I run a 57trim turbo, 850cc injectors and all the supporting mods. My block is bored .040 over - eagle crank - eagle rods - weisco pistons - balance shaftes removed - acl bearings - complete rotating assembely balanced and blueprinted.
My head: Webb 272 cams - crowler springs and retainers - crowler valves - new rockers - revised lifters, ect...

If my engine and transmission ( team rip stage 2.5+ ) are "bullet proof" then why do they say NO MORE THAN 20PSI????

At 20lbs my wideband reads in the 11's ( and thats with a keydriver ecu set for 850cc injectors and my AFC set at -25% under a heavy load. ) That leaves me with a range of fuel left to up that boost over 20lbs.

Turbonetics, Hahn, and Garrett all say "tune to 12.1 on your wideband" - as long as im not going leaner than that point is 20+ psi safe for my engine??

[xxShaneOmac]

I know alot of people that run 30 psi +
Shep runs 55 + psi on the same engine that is in your car.

20 psi is the mark where stock headbolts and HG's start giving out so thats the "limit" for say.

If your get thoes done, you good to up the boost.

Some people dont want to tune other peoples car at 50 psi cause they dont wanna be dipping into their pockets when someone else pos blows.

[turboglenn]

Throw some ARP head studs in there and go for broke! Just like Shane said, around 20psi is where the stock headbolts are still "safe" and there's agood amount of performance being cranked out also it seems the closer to 20psi and over you go the harder it is to control engine damaging detonation(on pump gas anyway).

The main reasons for the 20psi rule is that the stock head bolts start to lift in the mid to high 20's (25+psi) so they are giving you a good safety margin, and that pump gas withy teh stock timing curve starts to detonate pretty good after 20psi

I too have a garrett 57 trim turbo and on pump gas i keep it at 20psi mainly to avoid detonation, but when i pump in some E85 ( i'm tuned for it, you must tune for it just so you know) But anytway, on E85 or pump gas with really low timing i can run 24psi all day long and the 57 trim really starts to wake up right around there too.

I've been drinking at the bar for a bit so hopefully my grammar is decent and you can understand what i'm trying to get across. If you need anything clarified, just post up!

[kahl23]

It's called covering your own ass, they don't want to be held accountable for a new engine if your current one blows due to something they said or did. Like stated above if you have proper supporting mods crank that sucker, there's no reason not to, just realize more power=more stress on engine components. It sounds like you need to find a new shop.

Originally Posted by Turboglenn

I've been drinking at the bar for a bit so hopefully my grammar is decent and you can understand what i'm trying to get across. If you need anything clarified, just post up!

Well, you sound a little different than your more, shall we say, sober posts , but you're still coherent.

[gsxtasy]

Originally Posted by xxShaneOmac

Some people dont want to tune other peoples car at 50 psi cause they dont wanna be dipping into their pockets when someone else pos blows.

....and maybe because, 98% of the people with DSM's don't have a turbo that will even touch 50psi.

[my98gsx]

I think i left some things out of my parts list... Every bolt inside my engine is ARP... Main studs, Head Studs, Rod bolts... I also have a commetic MLS headgasket, so i sould be ok. I think since today is monday morning im going to do some calling aroud to different places- i want to solve this 20psi mystery mark.

[xxShaneOmac]

Originally Posted by gsxtasy

....and maybe because, 98% of the people with DSM's don't have a turbo that will even touch 50psi.

I was just saying, if I was a tuner tuning someones car at my shop, and I personally thought their car was a pos, I would put a real safe turn on it and tell him thats all.

He should be ok with 25 - 30 psi with all the mods he has.


P.s I was looking to custom my license plate and my friend told me to get gsXtacy

lol.

[xxShaneOmac]

Originally Posted by my98gsx

I think i left some things out of my parts list... Every bolt inside my engine is ARP... Main studs, Head Studs, Rod bolts... I also have a commetic MLS headgasket, so i sould be ok. I think since today is monday morning im going to do some calling aroud to different places- i want to solve this 20psi mystery mark.

There is nothing to solve.
If your car can take it. We have allready said stock cars cant, but your seems pretty modded and if in good health you can.

Turn up the boost, tune for knock to be safe if you are scared

[Smokin80]

Lots of people run 20+psi on a stock setup. Arp's are the only thing holding that back and i still ran 23psi for 2 years on a 16g with no problems at all. If you are built to the extent that you say you are(and im sure you are) then you will have no problems at all going beyond 20psi.

Happy boosting

[NewTurboTuner]

Well EVO guys have more money than the typical DSM owner.

These days DSM's are for cheap dudes and race cars.... thats about it.
The simple fact is that you have to Pay to Play. You can turn the boost up to whatever PSI you want too ....just be prepared to pay the price "IF" it fails.

I've been running my stock internal motor pretty hard for the last year. My lowest daily driver boost is 18-19psi, and up to 24psi <-Thats with a FP3065 @ 400+whp.

Last fall I ran up to 28psi and did 130mph at the drag strip. My motor is holding up great. I still don't see any signs of abuse considering I've been boosting hard ever since... and the motor is still running smooth.

Honestly I didnt think my motor would last as long as it has been. I had planned for it to fail at these boost/power levels. My last years plan was to build a race motor this year, but then I thought "why?" ....Theres no use in building a motor when my stocker is still running strong.


EDIT:
Also note.... that HP levels from psi is relative depending on turbo and set-up.
20psi from a 16g is not the same as 20psi from a GT35R, or the same as 20psi in from a GT42R.

[delta448]

Originally Posted by my98gsx

At 20lbs my wideband reads in the 11's ( and thats with a keydriver ecu set for 850cc injectors and my AFC set at -25% under a heavy load. ) That leaves me with a range of fuel left to up that boost over 20lbs.

Turbonetics, Hahn, and Garrett all say "tune to 12.1 on your wideband" - as long as im not going leaner than that point is 20+ psi safe for my engine??

As long as you have an adequate fuel pump, AFPR and logging ability, I say up the boost a little and do some logging. You won't know the limit of your particular engine and setup without some datalogging to let you know what's going on inside the engine.

Also, I recommend NOT tuning to 12.1 AFR unless you know exactly the thermal limit of your engine internals. Peak power is usually achieved with an AFR of 12.1-12.2, but most often a mix that lean will cause a slower and hotter burn, resulting in knock/detonation that pulls out timing. You should aim for a mix of no leaner than 11.5:1, as this is close to the mix which results in the fastest burn and least chance of knock. Then add as much timing as is beneficial. Once you find the Mean Best Timing, if you still have no knock, then you can start to lean out the mix a little bit at a time. Most likely you won't be able to advance timing enough to find the MBT with pump gas alone as fuel (unless you use E85, possibly).

EDIT : Oh wait... you don't have control over timing with the SAFC and keydiver chip... so nevermind. -Unless you go standalone, my advice is double check each time with a datalogger whenever you up the boost. I'm sure your chip is good for more than 20psi. You probably would be able to manipulate the SAFC and AFPR to go even a bit further once you find the limit of the chip.

[kittay]

That seems a bit ridiculous.. esp being on a larger turbo. I've ran my 16g on 24 psi. Alot of turbos don't become efficient until after 20psi..

[gsxtasy]

Originally Posted by xxShaneOmac

I was just saying, if I was a tuner tuning someones car at my shop, and I personally thought their car was a pos, I would put a real safe turn on it and tell him thats all.

He should be ok with 25 - 30 psi with all the mods he has.


P.s I was looking to custom my license plate and my friend told me to get gsXtacy

lol.

It'd make a good custom plate!

And i completely understand what your saying about the conservative tune.

[CanadianTSi]

Originally Posted by my98gsx

I got tuned last year and the shop refused to tune me over 20psi

I would definitely find a new shop or tune it yourself. With that setup you could (with a proper tune) run all the boost that Turbo could put out...

[spyderturbo007]

I've been running 22psi on the stock head studs and gasket for about 2 years with no problems. Compression hasn't budged at all and is solid across the board.

As Tyler said, crank down on that MBC! You didn't spend all that money to be running 20psi.

[TurboAnything]

Its all personal opinion i have a stock block with 131,000 miles on it and i run 32psi on 100 octane gas. I have run 14b's 16g's 20g's to over 30psi with no engine damage yet you just have to make sure you have a good AFR and no knock. There is no preset limit to boost on a 4g63 all cars are different.

[Black_Bullet]

Originally Posted by NewTurboTuner

EDIT:
Also note.... that HP levels from psi is relative depending on turbo and set-up.
20psi from a 16g is not the same as 20psi from a GT35R, or the same as 20psi in from a GT42R.

Basically ^..... And with that said, dont think so hard about boost itself, as boost can be irrevelant in a lot of cases, and you should worry more about how much power your engine can handle instead. Detonation is a much bigger factor in engine longevity as combustion pressures go up a substantial amount with a lot of knock.
Even people without arp headstuds dont really start lifting their heads until theres a lot of knock in the picture; ive heard of completely stock motors handle 25psi consistently. Then ive seen built motors running less boost but yet with such horrible tunes blow while the stock motor that was tuned correctly, made more power and never had issues.....

[mitsuclipsegsx]

I hope you didnt go back to VR. go here TheShopCT.com they tuned my car 24psi made 410whp...