how much boost is to much

[Sassan]

i have a 87 turbo supra and im about to buy an intercooler kit and a boost controller. my ?s are at wat point does the stock turbo max out? how much boost can i run on my stock engine without hurting it? and at wat point do i need or will i need a bov?

 

[Jay C]

I am sure more knowledgeable people will chime in to answer. However, if you have stock electronics and fuel system, your fuel cut will limit how much boost you can run. This is in place as a safety precaution. Before someone else posts it might help if you list what mods are already done to the car. If none I would think an exhaust and intake would be more beneficial than an IC and should both increase boost while reducing turbo lag.

 

[Sassan]

as of right now it has a 3in cat back exhaust that came with the car and stock intake.

 

[Supra87T]

i have a 87 turbo supra and im about to buy an intercooler kit and a boost controller. my ?s are at wat point does the stock turbo max out? how much boost can i run on my stock engine without hurting it? and at wat point do i need or will i need a bov?

Depends on condition of the engine and your fuel system. I would make sure that everything is in good order before upping the boost. An intercooler kit and 3" exhaust will increase the boost due to less restriction on the engine.

The purpose of the BOV is to relieve pressure and prevent compressor surge. You don't really need one unless the stock one is not working or is insufficient at relieving the pressure (probably not the case at this point).

Generally, 12-14 psi is about as far as you want to push the CT-26.

 

[Sassan]

my engine and fuel system is good. i know my car runs at 4lbs now. i heard that anything more than 8 and my fuel cut off would kick in. i was hopping for 8 to 10lbs nth much

 

[radiod]

Fuel cut on a stock system that is running properly with no boost leaks at sea level on a mild day (~60F) will typically be between 11 and 12 psi. And yes, all of those things will affect where it hits. You can usually hit 10psi without much issue assuming you have no boost leaks and everything is operating normally.

 

[Sassan]

i know i dnt have any boost leaks. and as far as i know my engine runs great. so i think ill start off wit 8lbs and see how my car does wit an option of 10lbs.
o btw wat is stop boost for a 87 turbo supra???

 

[OfnaRcR4]

i know i dnt have any boost leaks. and as far as i know my engine runs great. so i think ill start off wit 8lbs and see how my car does wit an option of 10lbs.
o btw wat is stop boost for a 87 turbo supra???

I don't know what stop boost is but if you mean fuel cut off, its generally around 10 or 11 lbs as previously stated.

 

[radiod]

STOCK boost in case that's what you were looking for is follows:

5.5 - 7.5psi for M/T
4.8 - 6.0psi for A/T

Reference: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=TC&P=5

 

[laotionracer101]

To much boost is when your A/F ratio gets lean, simply put you need to correct amount of fuel to coincide the the boost.

 

[GrimJack]

as of right now it has a 3in cat back exhaust that came with the car and stock intake.

How is your head bolt torque? Has the head gasket been replaced? If so, with what?

A catback exhaust is a good start, however, you need to replace the intake, turbo elbow, downpipe, and cat before you start delving into intercoolers and boost controllers. You should buy a real boost gauge and a wideband before you go there, too. And probably a real temperature gauge.

Alternatively, you can purchase the wrong parts, push up the boost, pop your head gasket, spin your bearings, and part out the car afterwards. We always need some more parts cars.

 

[WillWork4Boost]

A CT26 will push out 20psi but soon there after it's sure to go.

Plus a CT26 after about 14psi becomes useless, so might as well stick with that figure.

 

[RazoE]

It all depends on the health of your engine and your parts..

I have, with no boost controller, might I add, full 2.5" ic piping, larger aftermarket intercooler, 3" recirculated divorced down-pipe, HKS recirculated BOV, 3" dummy cat, and a full 3" exhaust, and I hit 11 psi, with no signs of fuel cut, and this is on a Non-turbo fuel pump (been meaning to upgrade that, but I rarely hit full boost by choice), everything is bolt-on. With tuning and a larger fuel pump, I can free-up even more power..

As mentioned before, a CT can boost pretty high, but after a certain point, you won't gain anything.

 

[laxboy36]

so what is a safe number to put on a boost controller bc i have a catback exhaust and im pushing 7.5-8psi and i need to know whats a safe number to put at with stock fuel system?

 

[OfnaRcR4]

so what is a safe number to put on a boost controller bc i have a catback exhaust and im pushing 7.5-8psi and i need to know whats a safe number to put at with stock fuel system?

This topic haas been beaten to death and is very easy to find via search but to save you some time anywhere around 10-12 pounds or just before fuel cut. If it hits fuel cut don't fret, just set it a little lower. This is all if everything is healthy.