gcb951

So I went to a local speed shop (ECS in Middletown) yesterday to pick up oil. I was at the counter paying for it and a guy pulls up in a pretty sweet looking 95ish Eagle Talon AWD. The car was black with gold rims and lowered. It had a really big front mount intercooler too. We got to talking and he told me that on pump gas he drives the car at 20psi all the time. I thought that sounded kind of nuts.

ilikemy944

Thats probably about right.
I drove around a 26/8 car at 21-22 psi on pump all the time.
VW guys are normally running 21 or so when chipped, even more when modded further...

ninefiveone

Why? different motors can handle different levels of daily boost.

gcb951

Huh, I did not know that. I have only had my 951 to about 13psi. The Vitesse kit says not to exceed 15psi on pump gas. I am afraid I will blow my car up if I go higher.

V2Rocket

remember he has a 4G63, basically the abrams tank of 4-cylinder engines

JohnKoaWood

Talon engine specs... plus they run a relatively SMALL turbo compared to the KKK 26-6 base...



PSI is only one piece of a complex formula... each manufacturer does it differently... effectively thay are running a 7cm exhaust housing (between the -6 and -8 that came stock on out cars) with a MUCH smaller compressor wheel (stock they run 406CFM... I believe the 26-6 is around 600 CFM... 26-8 is essentially the same compressor with a bigger exhaust housing)

they are small bore, long stroke low compression motors (8.5:1 stock) lower compression coupled to small displacement small bore long stroke motor running a smaller compressor wheel can inherently run higher boost for comparable performance.

They are a MUCH different design, and approach to making power compared to our cars... not to mention they are FWD (or AWD)...

So yeah for him running 20PSI boost, on a stock turbo is comparable to you running 12-13 PSI...

I have tuned my 951 at 15PSI... wild ride... but she started blowing oil, so I backed it back down untill I can rehab the 200000 mile motor...

ShApE

4g63 is bullet proof compared to out motors.

alxdgr8

20psi is week stuff on a 4G63. 30 is pretty much the standard. One of my friends runs 45 through a holset.

alxdgr8

Oh, and my S4 hits 17psi overboost stock. Most stage 1 chips change it to 20-21psi. RS2 specs (IIRRC it's based off a K26 variant) put you around 30psi on pump.

TurboTommy

Huh??????????

Running smaller compressors/hot housings (if reasonably matched to the engine) does not mean less power or stress on the engine per psi boost.
(If anything, it might be the other way around)

The compressors for the k26-6(8) are about 400CFM (not 600).

8.5 CR is not low. We have 8.0 CR; 930s have 6.5-7.0 CR (that's low)

And power to FWD means what, exactly????


To the OP;
if it's been suggested to you, by the right source, that you shouldn't exceed 15 psi, I would strongly adhere to that.
Don't get sucked in to all the talk.
That doesn't mean that the Talon guy was full of BS.
To those that say this motor is a fortress; what about it that makes it so strong? If detonation occurs, it's still going to ruin a motor with otherwise iron clad internals, no?

gcb951

The guy with the Talon said it was a 60hi fi turbo? I don't know if that was exactly what he said but he was talking about an external wastegate too, so that implies an aftermarket turbo. He also said the car had over 600whp. But earlier in the conversation he did mention he never had it on a dyno. So, how exactly does he know it has 600hp?

alxdgr8

No way it was at 600whp with a 60-1 hifi and only 20psi...no way at all.
My friend runs a Holset HX45 and dynoed 550whp at over 35psi

Chris White

John and I both are in agreement on the 15 psi number – but keep in mind that this is a ‘blanket’ statement. You are OK at 15psi for all conditions – including a 100 degree half hour track session at full throttle on a stock intercooler set up.

When a tuner/builder gives a ‘max recommended’ boost it does not mean that the engine will ‘blow up’ if you exceed it, it means that we feel that you can run at the setting anywhere, anytime for any length of time – with a little left for gas quality issues. In other words….its a bit conservative.

I have run a well instrumented car on the track and the 15 psi number is based on the increase in intake temps over a 60 minute full on session. At the end on the session the intake temps were high enough to warrant some concern of running any high boost – high intake temps will lead to detonation.

Can you run higher boost (at this point I will say this is me – not john – making this statement, I don’t want to put any words in his mouth!)? Sure, I usually tell my customers that 18psi is fine for the street – where you can only see full boost for short periods without getting jail time. If the gas is good and the ambient temps are not high you can run 20psi for short bursts.

The main thing about running boost higher than 15psi is that you have to do it intelligently – make sure the car is in perfect running order and pay attention. If possible have a ‘qualified’ person double check it. BTW – blowing oil on boost is a reason to keep boost in check!

I just ran a 2.5 engined race car on the dyno a week ago – 420rwhp at a little over 20psi, no problem!

gcb951

Glad to get your input on this Chris. I have traction issues at 12psi so until I upgrade my rims/tires I think I will stay around 12psi. I do want to get the piggyback that John sells but, just bought a house and I have to take care of a few things before blowing my money on car stuff again. Maybe Santa Claus can get it for me.

badcoupe

a few years ago I did a 4G63 motor for a guy with a 8 injectors and lots of $$ we got 1300+ HP at 38 lbs of boost. Sadly the car never got finished and the motor was parted out, alot of my time and research all for nothing!