This is my first RX-7 I bought off a forum member back in April '05. My first dyno run for my 87 TII was sometime in August when Steve Kan had a tuning session at Car V2 in Delaware. Right now, the engine is out of the car currently being rebuilt because of a cracked water jacket on the front iron.

This was done on a Dynapack. Total engine mods to date at time of dyno run are as follows: Corksport 80 mm turbo back, custom intake piping with K&N filter, Rtek 1.7, 720cc secondaries, and a manual boost controller set at 9 psi. Theres also a Centerforce Dual Friction clutch if anyone asks. I've wasnt expecting much more than 220 whp, but the graph speaks for itself. The second and third runs were a little less due to the top mount IC getting heat soaked.

 

That is a nice plot....what turbo are you running....that really doesnt seem like a stock compressor...the power was still climbing past 7k.

James

 

not bad, like wankel7asked... what turbo that be? please god do not say stock.

 

im with them , not a stock turbo , plus do you have a safc or any electrical tuning device besides a r-tek program and or is the motor a s5 or s4 the motor not the car. please give feed back very curious what was the temp outside was it really 88 degrees like the dyno sheet says?????????????????????????????????????????????/

 

9psi?
Definitely not a stock turbo!

Nice numbers!
That's like 260...270 range on a comparable DynoJet.


-Ted

 

Nice pull. What member did you buy it from?

 

Other than having extensive wastegate porting done by the previous owner, 3Turbos, the turbo is all stock to my knowledge. That particular day on the dyno was very warm, 88 degrees seems about right to me. The mbc was set to 9 psi, however I do remember that run had spiked to 10 psi. It was an original S4 motor, stock ports, with ONLY Rtek 1.7 ecu upgrade, no AFC or equivalent further tuning. Several other forum members and Steve Kan were there for that day, not sure if they would remember since this was a little while back.

 

I agree with everyone on the unusual stock turbo #'s, but WOW if it's true.

Did anyone you were with make any remark about the high #'s?

 

Stock ports too... weird.

 

eriksseven, everyone else there had a third gen but the few I spoke with congratulated me.
Has anyone else put down these numbers on 93 pump gas and these mods? Here's some pics of my turbo, let me know if this isnt the stock turbo.

 

Can you measure the major and minor diameters on the compressor wheel?
I think I see machining on the inside of the compressor wheel housing.

Sorry, but 9psi on the stock turbo will not support those kinds of power levels unless you're spraying NOS.


-Ted

 

the wheel looks stock, but the dyno chart looks odd, that power is pretty much impossible with the stock turbo and ic at 9 psi, unless its very lean and even then i doubt it. its a mystery

 

The compressor housing has been machined it looks like it may be a smaller TO4 wheel of some description. My modified Hybrid looks similar but it has had more machining in the compressor housing.

Regards
Michael Smith

 

Where and how is it visible that the housing has been machined? I dont have a caliper for measuring but I will try to get inducer/exducer measurements on comp. side. Any info on this not being the stock turbo would be news to me.

 

the compressor housign does look machined, but if you look at the stock one you will see it looks just like the one you posted the pics. so even the stock one has that "machined" look on the inside. are you sure that this is the turbo that is actually on the car and not some old pics?

 

Kahren, I believe it is in no way machined at all, nor do I believe the wheels are modified. I bought the car off a gearhead that explained every mod and replacement part he has put on the car. Im the third owner, I was told the first owner was an older woman that kept the car 100% oem, with the exception of an aftermarket spoiler. Those pictures were taken yesterday, as I am in the middle of my engine rebuild and the parts are scattered throughout my basement. If anyone wants to see it in person, Im located in West Chester, PA.

 

Forgot to add, upgraded fuel pump, emissions removed, TB coolant bypassed.

 

i was just wondering if you were teh one stakeing pics or if you had obtained them from the previous owner. but since you said you took ther epictures there is no more doubt. it all looks stock to me, i guess to make sure just measure the inuducer and exducer and you will know.

i still dont see stock turbo making that power, *shrug*

 

Good catch.
I didn't even bother looking at the dyno graph until you mentioned it.

It doesn't look like any typical 13BT dyno graph.
That dip after 4,000RPM is significant, and if this was the dreaded secondary fuel injector crossover hesistation, it's way too high.

Something just doesn't jive.
Can you get the car to dyno on another dyno nearby?
Possibly a DynoJet?


-Ted

 

The high peak before the dip was definitely a spike in boost beyond the mbc setting of 9 psi. It has spiked to 11 psi numerous times while driving, then will drop to 9 psi til redline. As you can tell from the pictures, my car isnt moving for awhile.

 

a spike wont change in such a way, it would be simply that a small spike, what you have is more like a boost change over a pretty wide rpm range.

 

Agreed.
Boost spikes won't drastically change power like how your graph is.

Can you get the car back on a dyno after you're done with the rebuild?
This would confirm if everything is kosher.


-Ted

 

wouldn`t it be more realistic if it were flywheel hp?

 

I think the graph you're seeing is just the wastegate opens. If you look at the chart, its only about 10ft-lbs when it opens, the way the dyno loads the engine is kinda weird from what i remembered and I'm not sure how much load it actually applies to the wheel as it sweep through the rpm range.

 

you guys do know the green curve is the torque plot and the blue is hp, right?