Bustadouglass

Hello all! Just got myself a 87' 951. Now is time to tackle the task of getting this out of shape 20 year old to run like an 8 year old after a icecream truck.

The current mods are: Cat back exhaust, Test Pipe, Intake, Blitz Boost controller, Tial Wastegate, Custom IC tubes, FPR, and I believe I was told either the head or Mani was ported. I have dyno sheets showing the car making 255rwhp and 305 rwtq. Yet she doesnt pull like id imagine it would with those stats.

If anyone has any answers to the following questions/concerns please chime in!!!

First- Throttle response/Lag. The response is a little hesitant. My Nissan Silvia jumps when I give it the slightest gas but the 951 is slow to boost unless im RIGHT in the peak of its power band.

Second- BOV. The Blow off Valve (Diverter Valve) is hesitant as well. It doesnt sound for a second after i let off the gas and when it does its just a whistle w/o the whoosh! It is an HKS SSQ unit. And i know how it should respond because I have the same one on my Silvia.

Third- Shifter. The shifter is soft and squishy. It engages well but in between gears it is loose as a noodle. Im thinking of upgrading to a short shifter but which is the best product?

Fourth- Suspension. This is the biggest thing for me. I just wanted to hear ppls opinions on setup. Mind you the car handles great but it is deffanitly showing its age with regaurds to the turns.

Thanks!!!

kasturbo

Where are you located? I'm going to guess Ohio given the screen name.

Bustadouglass

No im in Huntington Beach California.

turbo8

first and second are normal for these cars, get a MAF to help throttle responce, vent the bov to the atmospher if you want the woosh, not recomended though

ibkevin

Welcome to Renn!

There are thousands of years of Pcar knowledge here so I highly recommend you search the archives for your quests, at least initially. These cars have a couple of decades of performance mods available and many are documented in the archives section.

Go with the suggestions of the seasoned vets.

Bustadouglass

The BOV is already vented to atmospher. I want to recirc it but the way its in there I dont think ill have room to run the tubing.

How much will the MAF cost and what is the best choice? I believe I looked into the Autothority unit which looked good but pricy.

Yeah ill have to do some research but I havent had the time lately. Thanks for the responses tho!

Jaak Lepson

First off I would get all the vacuum hoses replaced ... makes a BIG difference. There are vedors out there who provide complete kits that include brass fittings and mini-ty-wraps.

For a BOV .. a 993 unit will be better than the original 951 and the small hose to hook it back up correctly

Check all of the intake hoses for leaks .. if in doubt ... replace them.

Check for exhaust leaks as well ...

Make sure all of the basics have been looked at and replace suspect components. Only then should you look at upgrades.

Try to find a copy of the workshop manual on CD ... there are lots out there and the code name is "coaster"

Bustadouglass

Where can I find the shop manual? And what doest "coaster" refer to?

Thanks for the info Jaak!

RKD in OKC

Take the BOV apart, clean it, use a light grease on it and put it back togther. You will find it works much better. The grease a lot of people use in these things can get pretty gunked up. Put the BOV on a vacuum gauge to see where it opens. It should open at 12 psi vacuum at least, but not over a maximum of say 18. If it opens sooner it will rob you of turbo spool. Think about it. The BOV is designed to open when you close the throttle. Closing the throttle will quickly create a vacuum in the intake and build perssure between the turbo and the throttle body. When you first open the throttle and start building boost, you get this same situation but not nearly to the same extent. If the spring is too weak in the BOV then it will open slightly when you first apply throttle or start building boost and add some lag. Aftermarket BOVs have a heavier spring and is why they are so popular.

I personally would plumb the BOV back to the intake where it is supposed to be instead of atmosphere. Partly because the metered air is kept in the system, but mostly because it helps balance the valve to operate better.

There should also be some adjustment on the Blitz boost controller as to the sensitivity, or when it starts to open the wastegate. If it is set too early it will cause lag, if set to close it will cause overboosting.

Short Shift kits are great, I love mine, but...the shifting rod, the long bar that goes from the shifter lever to the transmission on these cars gets worn where it connects. This is probably were you are feeling the looseness in the gates. They can be had pretty cheap if you can find a low mileage one at the recyclers.

Suspension so much depends on several things. How the car was used before you got it, and what you are planning to do with the car. Examples: I had an 88 Turbo S that the previous owner just loved to accelerate on the highway in 3rd. So much so that the rear torsion bars were shot when I got the car at 80K. I had to replace them because the car would bottom out in the rear when I accelerated with a stock motor. Another Example is my current 89, the spring and torsion bars are so worn on the drivers side of the car at 190K that it requires almost full height adjustment on that side and it is still just a little lower than the passenger side. Both situations mean to me that I need new springs and torsion bars. If your car is lower mileage the springs may be fine depending on what you want to use the car for.

If you are happy with the way the car rides and brakes and just want a little more cornering without the rolling loose feel you may only need some swaybars to make it a little more stable in the turns. I like adjustable ones like Weltmeister.

If you are planning to track the car you may be more interested in upping the spring rate for the increased corner loading. When upgrading springs on a non-turbo S it is really good to get something with adjustable perches so you can adjust the ride height and corner balance the car. Corner balancing makes a big difference with stiffer springs.