Turbo boost?
 

Ok, I have searched the files and really no clear answer to this. With the ARP studs, metal headgasket, no mods to the lower end, how much boost can the 7MGTE take? I have a boost guage on my car and it feels pretty nice at 10 psi, ( I have an adjuster for the wastegate) stock turbo with stock elbow. I know about the bigger exhaust facts and getting rid of the elbow and getting a better intercooler and better this and that, but without ARP main and rods bolts, how much has been pushed boostwise and had power and held together for a while?


Thanks

Russ

I am staying with the 7MGTE by-the-way, so no 1j or 2j suggestions please.

Stock bottom end will hold 500whp no problem, but if your are a high mileage person you should expect problems sooner than later. Duane (UpgradedSupra) has been running 30psi and 650+whp for a while without issue. He has a mhg and shot peened rods, that's it!! If you were to rebuild the motor with new rods, proper sized bearings and pistons it would hold 500whp all day long. Stock ct26 is good to around 14psi, higher it starts to lose efficiency so I've read. An upgraded wheel in a ct26 will get you in the 400whp range with supporting mods.

Not easy to answer as everyones engine has been beat in a different way. If you arent rebuilt you can expect to do it soon if you push it. 120k is getting up there on an original engine.

hopefully this comes close to what you're looking for.

Thanks. The engine has around 40K. The turbo impeller has a few nicks in it though with just a little bit of end play. When I bought the car it had a small diameter rubber hose coming off the wastegate and on it it has an adjustable valve that is used to adjust the boost level. If I open it all the way, the pressure comes on strong but then it abrubtly kills the engine, either fuel or electric. I don't know if there is a built in pressure sensor on the stock system or not. If I screw the adjuster all the way closed it seems to have its stock pressure of around 5 psi.

Is there a pressure sensor and can it be disabled? Will it cause a code to come on with the engine light? The engine sounds and feels good and has very good oil pressure, but again stock turbo, stock piping and stock intercooler. It has an aftermarket aircleaner and the previous owner put a 3" down pipe on it and removed the cat. converter. So I guess my question now is about a psi pressure sensor. I know it has a rev limiter, but this is different.

Thanks

Russ

You're hitting fuel cut, it's there to save your motor. Adjust your manual boost controller down until it no longer hits fuel cut. There are ways to raise this like the lexus afm with 550cc injectors or a maft pro. Factory fuel cut is between 11psi and 13psi. A little different on every car from what I've read.

Ok, then there is a pressure sensor. The adjuster is just a cheap piece that works but nothing more than a brass valve. So the Lexus afm and the larger injectors allow the sensor to allow for more boost? And curious about the maft pro, guess I can do a search at other aftermarket sites.

I have lowered the boost sense I did hit that cut off point so it boosts smooth again. Is that sensor hooked into the reading from the stock guage? I notice that the guage only goes to 8 psi. If some guys are getting monster boost levels, I was wondering just how they got around that cut off point.

Thanks

Russ

For the turbo experts, How much hp could i expect from a stock 7mgte(auto trans) with rebuilt head and turbo, Brand new toyota headgasket and torqued arp head studs, Intake/exhaust/mbc, And no other mods except a mk4 intercooler nad hardpipes and as good of gas as i can get? This is all i plan to do untill i can afford an entire extra motor and rebuild. I know i can only get to 14 psi or so before boost cut, But i plan on keeping it about 11-12 just to keep everything safe and unbroken. So basically, Allt hos parts and running 11-12 psi.

You'll hit fuel cut around 11psi, at that point you'll probably be around 240whp.

hmm 240 is still good enough for me. What boost can you run with the lexus afm and 550 cc injectors?

how much boost can be ran without needing an after market fuel regulator?

240 whp at 11 psi? That is only a 10 horsepower increase from stock. Whats with that?