How high can I turn up boost on stock engine?

[MidShipCivic]

I have a red 89 turbo with afc ( not dynoed tuned or adjusted yet) with a greddy boost controller. I've full throttled it on the interstate and it hits 15 psi and I get no fuel cutoff it's momentum at that level is like a frieght train.

I dont have my wide band so I cant tell.

I was in on it for 5 seconds at least is it okay that I'm doing this?

 

[johnathan1]

WOW...15psi on a stock engine? Sounds like you're asking for trouble...has the head gasket at least been replaced? Intake or exhaust?

Also, you should hit fuel cut at around 12-13psi.

 

[isnms]

...is it okay that I'm doing this?

Can't tell without a wideband.

 

[MidShipCivic]

I think it has been adjusted with the afc then.

Electronic boost controller
Greddy Turbo Timer
SAFC2
SSQV BOV
Boost gauge
3in Straightpipe turbo back

 

[NA86.5]

12psi stock sounds right for the fuel cut

 

[MidShipCivic]

It's just been bought 3 days ago bearings & rods been replaced with new oem rods so I think it does have something. It's giving me whitish smoke on decel ( No not BHG, but no catch can and I see no PCV) Bluish kinda no cat would cause this?

 

[johnathan1]

Smoke on decel is usually turbo seals or valve stem seals.

Also, you don't have any sort of PCV system? The stock system isn't there? Stock headgasket?

 

[s383mmber1]

WOW!

I love the look of your supra for some reason! So clean!

O yeah, btw,

15 psi, stock headgasket, no wideband = NO!

 

[Mr.PFloyd]

and for some reason it doesnt look like oem red..

 

[MidShipCivic]

Smoke on decel is usually turbo seals or valve stem seals.

Also, you don't have any sort of PCV system? The stock system isn't there? Stock headgasket?

No PCV valve on hose. Car has been repainted also.

 

[americanjebus]

On a stock block you can run upwards of 400+ hp, its all in your tune, you could grenade the thing at 250hp if its not being checked with the wideband. As for the stock headgasket, if its still there i'd be warry of more than 350hp depending how smooth you get your a/f ratio curve.

 

[johnathan1]

There is not supposed to be a PCV valve...7M's don't use one.

 

[xarewhyayen]

the 7m doesnt use a pcv valve, its an open orifice PCV system... i'd suggest running less boost if you care about the car lasting at all... with the stock fuel system and the chance the SAFC is trimming fuel which is gonna spell lean, youre probably gonna grenade the engine at some point.

I'd spend more time on the forums researching the right way to feel the true power you can get outta this motor rather than learn the hard way what not to do.

Anyway.. car looks nice.. just be careful with it

 

[Boost Lee]

What does your vacuum rest at during idle?

It's very possible that you're boosting 15psi...but not likely unless you've backed out the AFM screw that allows more unmetered air.

Reasoning for asking of how much vacuum you're pulling is because you could simply have a vacuum leak somewhere that will throw off your reading a bit.

-Jeff


*EDIT* xarewhyayen is 100% correct. 10psi, with a complete and healthy tune will pull harder than a rough edged nasty 15psi.

 

[MidShipCivic]

I just did it once and the car instantly hit 130mph, I didnt do it again it's doing 11 psi right now.

Vacumm at idle is 11 in/hg.

Crazy white bluish smoke on decel thats the turbo seals? The charge pipe that goes across the valve covers are clean, but the outlet pipe right after the intecooler it's oily inside.

 

[xarewhyayen]

11 inches of vaccum at idle is pretty low..edit.. really low. Check for vac leaks

 

[supradan22]

Thats Pedro's old car my friend was gona buy it.

I think it has a new bottom end and a new HG

 

[MidShipCivic]

No its mines now.

 

[supradan22]

Oh yeah be carefull with that car he has a FCD on it too thats why your not hitting fuel cut.

 

[MidShipCivic]

How do you introduce an FDC to the car had and it (still has) alot of charge pipe leaks too. I'm trying to figure why its smoking on decel.