boost, but how much?

[J's91supraturbo]

Hey everybody- I've got a 91 Supra turbo, stock 7m-gte. I bought a manual boost controller, but have not installed it yet. I was told that the stock boost guage is not accurate (at all) and that if i'm gonna mess w/ the boost I should install an aftermarket boost guage. Is all this true so far?
Ok, back to topic, so my motor was rebuilt by someone else, they said they put arp head studs in, but I don't know about the metal head gasket. If I DON'T have the metal head gasket, how much boost can I run w/o fuel injectors... I know a guy who ran 14 in his 89 supra for about two months, but had a major ordeal after that. Oh, and is a EGT guage a good idea? Sounds good to me, just figured I'd ask some people who know a little more than I do!
Dang, here I go again, so many questions! Turbo Elbow, and Exhaust.... I was thinking about having someone mandrel bend me some 3" exhaust, is there anything I should do with that, cuz I was thinking no cats and a single muffler, 3" all the way. Is the turbo elbow and a downpipe the same thing? HA HA. Someone on here said they had a 2.5" reducer, is that necessary?
Oh, and I know I should do an intake, is there a good, cost effective system? I don't want a cone filter duct taped to the intake tube, but a simple, cost effective solution would be sweet!
I'm sure I have way more questions, but I guess this is a start! Thanks for any help!

[Jeeves]

That's true. The boost gauge (from what I've, and other have seen) is an on/off gauge @ 4psi, and is incredibly slow throught the rest of the swing.

The guy running 14 wasn't running 14 without a FCD, a VPC, a MAFT Pro, or the like. Fuel Cut Off is at ~12psi. It's a limitiation you can't really get around. The fuel system is not strong enough to run more than 12psi in stock form. I wouldn't suggest running more than 10psi.

With wideband's more and more common, EGT's are almost worthless. There are better instruments to use nowadays for what an EGT does.

No, the elbow and downpipe aren't always the same. Newer downpipe incorporate the elbow into the downpipe, but the stock stuff is separate. Personally, I'd run a resonator in that exhaust system but that's me.

Go get a K&N Drop in filter for the stock supra, that should treat you good.

[J's91supraturbo]

I'm running ngk 7's right now for plugs, any suggestions? These have been in for 10k miles, and seem to be doing just fine! I think I'll run them til I start getting a misfire, just to see how long they last. As for the resonator, is that just for the sound? A friend of mine says "the best exhaust for a turbo motor is none".....is that true? So 10psi would be a good place to keep it then? Ok, what is it supposed to run stock? Because it looks like it's running around 6.......but it's not like the stock guage is numbered very well! Could I make a resonator, or is that something I should purchase somewhere, I know my boss got a cat eliminator for his maxima.....but he says I don't need that even! Any info would be a great help! Oh, another thing, my synchro's seem to be kinda slow in 1st, 2nd, and 3rd, but only on downshifts, not on upshifts, is there any trans additive that you would suggest? I already changed the fluid....no change. Thanks a ton!

[Jeeves]

NGK Coppers are the way to go for 7M engines.

The resonator is just so things don't drive you insane, most good exhaust (see, HKS Dragger Exhaust) setups have two after the cat, before the muffler. What your friend said is true however. Turbo cars want NO pressure on that turbo side, they want to get rid of that exhaust and spin the turbo faster. N/A cars, however, require a bit of backpressure to operate well.

10psi is a good location because it's below fuel cut, so you shouldn't spike and hit it, but it's enough to give a very healthy bonus to the car's motion. Stock they list at 6.8psi, but there is a 2psi drop across the intercooler, so it's more liek 4-5psi at the manifold stock.

a resonator is a part that is welded into the exhaust pipe.


You can buy a 3" test pipe, or a high-flow cat to replace the factory one. You'll need a cat of some kind to pass emissions. However, as our cars don't have OBDII, you don't have to worry about it throwing a check engine light when it doesn't have a cat there.

All synchro's are fuckered after years and years of abuse, only one thing has been shown to play real nice with them. Redline MT90 Transmission fluid. It helped my synchros a helluva lot. In a month or so it shifted like a whole new car. Additives aren't generally good.