I have a stock 87 turbo fc.. with cat back and a fuel cut defender.. I was wondering what should i run boost wise if i wanted to turn it up a little and still be "reliable"

 

i would say 10psi max for reliability

 

5.5psi

 

Stock boost until you do fuel mods.

 

Stock boost. Toss the FCD in the trash, and go with something that doesn't screw with the boost signal if you're intent on running higher pressure. Fuel pump, injectors, fuel control.

 

Aright man thanks.. also.. I was thinking of going with a 13bre when my motor blows.. Does anyone know if there worth doing the swap..

 

Take care of the engine and it wont blow up.

 

more boost on stock fuel isn't reliable, without doing some checking/maintenance.

the stock turbo fuel pump has no extra capacity. it is important that the filter both in the tank, and in the engine bay are new. also its a good idea to check the fuel pump voltage, if its too low, then the pump will not supply enough fuel. sometimes this even means redoing the charging system harness!

plan B is something like an FD fuel pump, if you've got a friend with an FD, just take his stock one, it'll be sitting around.

the stock precat/dp sucks, it creates a TON of backpressure, which is BAD for a rotary. however i used to see 13psi on cold days, and the STOCK S5's run 8.5psi @peak boost.

so if you have the fuel system sorted, 8.5psi is fine, 10psi is on the high side for stock fuel, it can be done, but you should be considering bigger injectors and or an ECU upgrade.

 

"the stock turbo fuel pump has no extra capacity. it is important that the filter both in the tank, and in the engine bay are new. "

True that. Inexpensive maintenance yielding comparative high return

"also its a good idea to check the fuel pump voltage, if its too low, then the pump will not supply enough fuel. sometimes this even means redoing the charging system harness! " "plan B is something like an FD fuel pump"

1. Run a heavy gauge wire directly from the battery, 30 amp fuse in between, back to the fuel pump area. Cut the wire providing the stock "hot" to the pump and run it to the trigger side of the relay, the new "hot" to one side of the relay, other side to the wire running to the relay, and of course wire to the chassis to ground the other side of the relay trigger circuit. This will eliminate very common voltage drop the stock wiring will provide.

2. Agree, replace the stock fuel pump with one from an FD, or buy a Walbro or Denso aftermarket fuel pump. Very easy install process.

Goal for 1 & 2 is to help insure you don't lean out on your fuel. You lean out, pop does your engine. You might want to also invest in an EGT gauge or Wideband (narrow band that sources off the ECU is only good for entertainment value, not meaningful information) gauge so you can keep an eye on things so to avoid this dreaded leaning out.

Cat back by itself won't change boost, so I'm assuming you'll be installing a boost controller to up the boost. In the alternative, a RB downpipe and presilencer will get you to higher boost all by itself. Full REV II better still.

With all the above I'd still limit yourself to 7-8.5 lbs boost if you're running the stock ECU. But that should get you kissing 200 rwhp.

 

Motor has 150k miles.. it will eventually blow up

 

@ 8 psi wont blow up .take care of it. oil change plugs. etc had a t2 with over 200k

 

^ same here. Eventually any engine will give it up. But I also got 200,000 miles on my old 87 TII before a water seal crapped out. You could have a couple years life yet to go on your block if you treat her nice.

 

Key word... "Eventually"

 

Racingbeat says that the stock apex seals are good to 12PSI of boost.. So I would say that the stock internals are good to 12PSI.

 

Where the hell did you hear that?

 

Quote from the RacingBeat inc. Rotary performance Technical Manual

"Cast iron (stock) apex seals are best for many applications. as long as you never exceed 8,500 RPM (RX-8 - 9500rpm) and dont run the engine highly supercharged (not exceeding 12 PSI of boost) the stock seals will "seal" better and last a long time."

 

That may be fine as a blanket statement, but psi alone doesn't have very much of a direct affect on the amount of stress the apex seal has to cope with.

Detonating at 12psi on a stock turbo is NOTHING compared to detonation at 12psi on a GT45

 

I would say that ANY kind of detonation is a issue. With any kind of turbo.

I'm pretty sure that racingbeats statment was not factoring in any detonation. since a properly tuned engine will not be detonating...

I trust what racing beat has to say.. after all they have been building these engines for over 35 years. They also have broken bonneville salt flats speed records, have won plenty IMSA championships and won there share of NHRA drag racing with rotarys...

 

whats your hurry? isn't it hard enough to find parts for these things?

actually @120k if you're going to start leaning on it, it might be a good idea to rebuild it FIRST. chamber sealing in the engine is CRITICAL.

 

Nope not really.. and what do you mean?