It might be efficient on paper up to 29psi, doesn't mean it will go to 29psi and hold it

 

According to RPM, the turbo is efficient up to 27 psi without generating excessive heat.

 

Rob you're just jealous.

 

From my dyno sheet, does it look like it was going lean up top?

 

i'll let you beat me for two weeks then you'll be back to normal
remember my car is still basically stock...


I think the problem with your car is the piece behind the wheel is no good

 

Surley that is a very generic statement isnt it ?

I mean are they saying the turbo will be a perfect match to a stock ported 13B at that pressure ratio, what about bolt on's or porting that significatly increase flow rate of the engine (without increasing the pressure ratio) ?.

I think it will be real interesting now that quite a few guys are pushing the power potential of this unit @ higher boost levels to see what it can do on various 13B engines.

 

Currently just HKS twin power, no break up on the top end.

K

 

Hey angus, are you familiar with car test 2000 ?

I just ran an analysis and got these numbers, I used a gear shift time of 0.3 seconds and engagment time of 0.1 sec. set it up to run 1.38 60 foot times !
runs 10.1 @ 137mph !!! In our cars, I estimated your weight at around 1180kg with driver ? with 5 speed T2 box and a Gt35/40 power curve with peak engine BHP set @ 525 to 530 bhp or about 460rwhp dynojet talk. i used a 8000 to 8500rpm launch speed with optimal shift points.

This is a pretty good program, I have used it to back up some of my on road data logs of my Autronic overlaid with my current power graphs and the results are remakably accurate.

Does this agree with some dyo graphs you have? what do ya rekon....cheers.

Pete

 

A great program, one of my favorites.

http://www.cartest2000.com/

Ken

 

I wasn't doubting you, just saying how nice that increase was

 

Hey Peter!
Just for reference the 3rd gen(series VI) Rx-7 here normaly loose 12 to 15% horsepower in complete stock form when measured at the wheels on the Dynojet.
Wheel power usually check in around 210 to 215 some as high as 220 hp. They were rated at 255 flywheel horsepower.
I also got a road race buddy with a 1st gen(series I) Rx-7 that we had the motor dynoed on an engine dyno and it made 260 hp at the flywheel and we later dynoed on the dynojet and it made 220 hp. Conditions on both dynoes were pretty close since they are located only a couple of bays away from each other. Also when we dynoed on the engine dyno it was with all the same accessories on the motor as it would be on the car even the exhaust and ignition system.
BTW. it was a street ported 12A with dual 45mm weber carbs!

crispeed
87 RX-7 TII
9.204@150.47mph
2600lbs
un-tubbed

 

Excuse me while I go hunt down a TWM dual DCOE intake manifold...

 

We fabricated our's!
It's much better than any of the ones I've seen out there.

crispeed

 

Ihor,

What INJ duty cycle were you running? I am wondering if you were running out of fuel too. Have you upgraded your lines? I know you have the Cosmo pump (time for Bosch!). Do you have a log of that dyno run? If you don't and want a graph like I made for my last dyno run, I'll set you up.

Great runs. I think there is def. some more left in there. Did Dave mess with the IGN or SPLIT at all? Betting to see more RWHP at lower boost levels with some FINE tuning.

Tony

 

I would be getting a diff before actually trying any if this

 

can someone help me out on the dyno sheet on the first page. with how everything was setup, where can you tell where boost was building? im new to interpretting dyno sheets. im curious as to the spool rate of this turbo as it may be in my future. anyone please? silver ninety three??
kris

 

I would say from looking at it the boost starts as soon as the test started and builds quickly, reaching it's peak or near it's peak by 3800rpm. For sure by 4k looking at the rate of torque increase from there it looks as though it is engine realted factors that are increasing the torque in a more normal way, but yeah, it looks like the "boosted torque" is happening till almost 4k, you can pick this by the almost exponential increase in torque which is a indicator of turbine/compressor speed, for every doubling of shaft speed you get about 4 times the air flow and you can see this over the very short rpm span from 2.6k to 4k rpm's which means boost was building like crazy to this point (almost uncontrolable, till the wastegate opens up to bypass the gass flow to the turbine and hence stabilize the boost build up, after this point you will notice the torque curve is more sedate and is changing mostly as a result of the engine porting and manifolding, and other acessories etc.

Now you know the trends have a look at my graph (similar power range and same boost setting, but with different sized turbine/exhaust housing)
https://www.rx7club.com/forum/attach...&postid=773080
You will see that if you apply the same analysis that I am making most of my boost by about 5250rpm or there abouts, then engine and system set up take over from then in a much more "controlled way" NOTE THE EXPONETIAL apperance of the torque and power curve to 5250rpm, this is the give away to the building of near maximum boost.

The gt35/40 looks real strong, nice balance between realy strong low rpm boost and enough power for a street/track car for all but the hardened enthusiast ! Ideal for autocross I would say for people who want low down grunt, it has a definated advantage to 6k rpm (by this rpm point it is about 5% more powerfull, then as you near peak power the larger turbine seems to have a bit more grunt to it, hard to say unless you tested these turbo on the exact same engine/system set up) I would say there is a very clear advantage from 2.5 to 6k with the more modern smaller exhaust spec turbo on a street port. I definatley would not do rolling start race against one with less than 5k rpm on the dial

 

I'd like to see a test of this gt35/40 turbo similar to the run I did on my XS T04e kit. I know mine is less powerful and a lot cheaper. If you have this kind of boost increases than you sound like you have a great low-end streetable turbo in my book.

"I did a test on boost lag today. It's 32F degrees today. I did it in 4th gear and started at 2k rpms WOT. I used my autometer boost gauge. I set the Profec B at 20psi boost. I still have 100 octane fuel in it. At 2500rpms it was at 8psi, at 3000rpms it was at 15psi, at 3500rpms it was at 20psi.

It's funny because the roads were a little damp and it looked like the tires would have broke loose at 20psi. I felt the traction control kick in and cut wheel spin. I had it set for 10% slippage.

I hope this was a good test. I'm satisfied to get max boost at 3500rpms.

Ken"

 

Badog, duty cycles got into the mid 80's at 20 psi. I think I remember seing 84% or something. The cosmo pump is supposed to be good for 500 hp, but I don't think I will push it any higher with this pump. Not enough margin for error. I might get another cosmo and run them in parallel. Fuel lines are stock and I have an sx rising rate 1:1 fpr.

 

Ken, I can get 15 psi but 3500 rpm, which is plenty fast for me. The to4e is alot smaller, so it should spool faster. Can you really get 20 psi at 3500 rpm? Seams mighty fast. Also, is 100 octane enough for 20 psi?

 

If I get a chance, I'll go and buy some race gas today and do some more spool tests.

 

Ya, I did two tests and the Autoeter had it at 20psi at 3500rpms. I was surprised too. KDR said 100 octane would be a breeze at 22psi as I have water injection.

Ken

 

When I say 100 octane I mean a mixture of 110 octane with a mixture of 92 octane. Currently I get 110 octane for $2.90 a gallon(Mobil station with Phillips racing gas).

Ken

 

I just threw together a little Excel plot on Ihor's GT 3540 and LETHAL RX-7's T-78. I used tire height, rear gear, and our 4th gear tranny ratio to determine the rpm for the T-78 since it was in mph.

https://www.rx7club.com/forum/showth...threadid=144021

https://www.rx7club.com/forum/showth...threadid=142247

They are virtually on top of each other from 3000 rpm up. With the GT 35/40 being *more* peaky than the T-78. I know that the conditions were different, ect ect, but I wanted to get an idea as to how much quicker the 3540 would make power than the T-78 on the average street ported motor. The 3540 may indeed spool quicker, but it doesn't look like makes any more power than the T-78 in the 3000-5000 rpm range -maybe because of flow? These were on the same dyno and around the same boost, BTW.

I'll try to attach the spreadsheet. I guess time will tell once we see some more dynos. Both have very nice numbers -just trying to decide which!