I just got back from the dyno, here is my car:

1987 turbo rx7 (stock engine internals)
Greddy FMIC
3" intake with large k&n
760 primary 850 secondary
RB Full exhaust turbo back
RB FCD (just kidding)
1990 Turbocharger with ported w/g and
upgraded compressor (like a t4 or something, dono)
Walbro fuel pump
Paralel fuel system running 38psi static rising rate 1:1
Smog removed

The car pulled outstanding numbers on the dyno. First I wanted to be in the 250 range, and I was blown away when a 300.8 rwhp showed up on only the first pull!! 250 tq. It was staggering, I told him to retard that timing NOW so he did. I drove home with 290ish to the wheels.

No a little about actual sitting on dyno. The person never knew about Microtech until my call a month ago for time scheduling. My car was the first Microtech he had done. He actually had a crowd of RX7 people waiting to see this thing in action. At first things were very rich. We cried as the engine reved basically. Basic tuning was done for about an hour or so, just pinpointing coarse details in Matrix Mode (he wanted rpm abilities). He loved tuning it. Only took him 2.5 hours, of corse there were complications such as my intercooler pipe blowing off, ebrake stuck and pads smoking, and a stupid vacuum cap blew off the back of the motor. He red-lined at 7k.

The action of the turbo went like this. No waste-gate control other that a single vac line running from top of turbo to waste-gate. OK so it would hit 6psi in a real hurry. After about 4500 rpm it crept to 13 psi (4th gear pulls) and my hands started shaking with fear of engine blowing. I talked with a much older fellow right at the dyno about fitting an aftermarket w/g onto the stock turbo. Apparently he did this and had great success. He'll do it cheap for me.

Well thats about it!!!! Keep an eye out in the forum (saabguy) for a dyno posting under Microtech forum. I'm just waiting for emails of the dyno sheets. I will also post 5 datalogs for everyone to look at.

Eric Stoehr

 

Zip file contains 5 log files which may be viewed in laptop software.


Can anyone maybe tell me why my boost fluctuated rapidly above 10psi???? My boost guage held steady at 12-13 psi.

 

This is the dyno of the 300.8rwhp. Note there is no a/f ratio chart. It was really quite untuned at first. Honestly, the engine pinged. Now my timing is more retarded and fuel richer.

I love this world

 

Nice work.

 

Which model FMIC do you have? And stock ports, awsome....

 

Its a greddy fmic 24v or something for stock turbo.

All engine internals, intake manifolds, and exhaust manifolds (s5) are stock.

 

Could you get some better specs on the turbo please? I am curious.

Nice numbers btw!

 

what was your timing map like?

 

damn beautiful numbers congrats!

 

My turbo??? Um OK.

I bought it used from someone for 150 bux in good working order. The hot side is a stock s4 turbine encased in an s5 housing. The manifold is s5, wastegate s5. Wastegate is masivly ported.

The compressor I am unsure of to this day. When I bought it, the person said it was a Grand National Compressor as he bought it used from somone who said it was a to4e. It is not a to4e, but it very well could be from some sort of Grand National (or GN upgrade like on turbonetic's website). The backplate on the compressor is colored RED (Someone said that makes it look like a t4). Compaired to stock turbo it is 1/2 inch more in diameter inlet, outlet is about 1/8 inch larger than stock. I've looked at compressor maps and the closest I can find is the "T3 SUPER 60" but again thats another monkey wrench for the mix. All you need to know is that its larger than stock!!! Air temps never rose above like 32 degrees C with FMIC.

John, heres your timing maps, 5 of them zipped into one file. I use Sonoco 94 octane (premix)

 

Also when I got home, I trimed the timing -1 degree and also trimmed the injectors +1% (I feel 1% safer!!)

 

That was my old turbo baby, I knew it was good but not that good, lol :eek

This turbo came from turbo city.

C


:

 

It sounds like a To4b hybrid. That's about the power it should make and I know more than a couple people running them from Turbo City.

 

What do people think of my a/f ratio?? Looks wavy I know. This was a tail pipe sniffer.

 

Nice numbers! Do you have a micrometer? If so could you measure the comrpessor wheel for us?

 

Is the wheel upgraded, or just the housing?

 

Timing map looks reasonably close.Your Dyno guy seems pretty switched on which helps!
Another hint to solve some eratic pinging problems is to get the crank angle sensor right away from your plug leads & main alternator wire.
The crank angle wire is very sensetive to electrical interference & both of these can be a big cause of it.
Cheap plug leads are no good either.Magnecor & NGK are by far the best over here if you have them there,use them!

 

The entire compressor is upgraded. Larger housing, larger wheel.

When I get home I will post some pictures compairing the stock s4 turbo vs this modified s5 turbo.

 

Those results are awesome, Eric! I think the bouncy AFR could be tuned out with a bit more time, and is simply an effect the LT8 being a new system to the tuner.

The boost fluctuations are normal. Your boost gauge is damped to prevent such oscillations from showing, but they're always there.

Follow Jon's advice and route the CAS bundle away from large inductive sources like spark plug wires and your alternator, and things should probably improve a touch.

Other than that, it looks awesome! How are things like low-speed driveability and cruise? What MPG are you getting?

Congrats, mate!
Brandon
BR7 Racing

 

Low speed and cruise actually have decent throttle response now.

I worked a little on the dips in the a/f line. I lowered when the secondaries kick from 3500 (reccommended by John) back down to 3000 and gave a bit more fuel in that area (folowing datalogs.) The second jump from 4 thru 5k have also been worked on. I found a few dips in the matrix map at said rpms and loged psi. I raied the ms values in these areas.

Other things such as mass timing retard of 1 degree and mass mixture trim enrichenment of 1% makes me feel a little better! Maybe soon I will organize a dyno day and get another few readings in a month or 2.

Milege looks very good so far. ive been beating on the car a bit more than usual and it looks like 20 +/- is going to be the average weekly mpg. Low speed drivability is great. I do get a few hickups here and there but I think its pump1 and pump2 settings.

 

Congratulations on the numbers. Makes me feel even better about what my car will be like, when it's done.

What do you run in the quarter mile?

 

The guy at the dyno deals with 700+ hp cars and does drag racing regularly. he said that I have a good chance at hitting a low 13second run, so i dono what to think.

 

With about 300rwhp, you should be faster than that. Theres people with about 200rwhp in 13's.

 

in my first gen with 190rwhp i ran a 13.3@105, then changed the turbo to a small t04 and went 11.7 with 270rwhp, then fitted a 60-1 and went 10.9@125 with 407rwhp,
with your 300rwhp and a good launch you should see a very very easy 12sec pass,

Dale

 

Thats what I was thinking. Low 13's? **** He must have meant low 12's. Just practice practice practice that launch.