How much power does a 4.5 liter with two IHI RHB-6 Turbochargers really make?
11-27-2003, 11:37 AM
#17
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I think Wisconsin schools need to start a new math program called "Turbo-Math". Really, it is nothing personal I'm honestly just having fun...
I will go to scan the dyno charts today or tomorrow and post as soon as I can. It is Thanksgiving and my Birthday today so it may have to wait until tomorrow. The Dyno runs were my birthday gift to myself. My goal was to finish this project before my wedding and I have done it (but just by 10 days...aka skin of the teeth!) I could write a book on "how to let a 928 consume every spare minute of your life"
I still have some low end off idle fuel tuning to do but I already had several hours on the dyno and it is best I do it on the street anyway. Now where the heck are those plans for the $230.00 wide band O2 kit I remember seeing?
A couple of things....I know for a fact that I will have better charge cooling out on the highway at speed and I know for a fact that the car generates more boost out on the road than it did on the dyno, maybe 1 to 1.5 psig more. I'll just say that it is within striking distance of 400 HP at the wheel.
Somebody please stop me from shimming these wastegates.....for now that little button under the dash is worth nearly 70 HP to the road. I am quitting while I am ahead...I never set out to build a bomb.
I will go to scan the dyno charts today or tomorrow and post as soon as I can. It is Thanksgiving and my Birthday today so it may have to wait until tomorrow. The Dyno runs were my birthday gift to myself. My goal was to finish this project before my wedding and I have done it (but just by 10 days...aka skin of the teeth!) I could write a book on "how to let a 928 consume every spare minute of your life"
I still have some low end off idle fuel tuning to do but I already had several hours on the dyno and it is best I do it on the street anyway. Now where the heck are those plans for the $230.00 wide band O2 kit I remember seeing?
A couple of things....I know for a fact that I will have better charge cooling out on the highway at speed and I know for a fact that the car generates more boost out on the road than it did on the dyno, maybe 1 to 1.5 psig more. I'll just say that it is within striking distance of 400 HP at the wheel.
Somebody please stop me from shimming these wastegates.....for now that little button under the dash is worth nearly 70 HP to the road. I am quitting while I am ahead...I never set out to build a bomb.
11-27-2003, 01:13 PM
#18
Great news John! I can't wait to hear what you got on the dyno. I'm sure with more tweeking you will be able to bump this number up some more too.
Andy,
Yep it was on one of my other German cars, but it is fun none the less.
Andy,
Yep it was on one of my other German cars, but it is fun none the less.
11-28-2003, 10:32 PM
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Okay, I have the sheets scanned but can't seem to get them loaded....who would like to post them for me? I have two graphs....the one off of the dyno and the other is a graph showing stock vs. modified HP.
11-29-2003, 02:35 PM
#24
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Monster numbers from a U.S. spec 4.5 liter John, well done!
Maybe there is something to all this speculation that the 928 was built for forced air induction in mind.
The ramp of your power curve is pretty steep, it must feel like being shot out of a cannon when the tach sweeps past 4K rpm. Yeehaw!
Maybe there is something to all this speculation that the 928 was built for forced air induction in mind.
The ramp of your power curve is pretty steep, it must feel like being shot out of a cannon when the tach sweeps past 4K rpm. Yeehaw!
11-29-2003, 02:46 PM
#25
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John,
Go back to the dyno place and have them drop your runs onto a froppy disk. Filenames are usually 'YourName.###', eg. 'DynoRun.001'.
Then download the free Dynojet run viewer and you can make your own graphs! It's pretty easy to use.
If you have even a simple drawing program, you can cut and paste the screen shots of the viewer by using {Alt}+{Prt Scr} (print screen button).
The bozos at my dyno place printed everything but what I wanted...
Download here: DynoJet Run Viewer
Go back to the dyno place and have them drop your runs onto a froppy disk. Filenames are usually 'YourName.###', eg. 'DynoRun.001'.
Then download the free Dynojet run viewer and you can make your own graphs! It's pretty easy to use.
If you have even a simple drawing program, you can cut and paste the screen shots of the viewer by using {Alt}+{Prt Scr} (print screen button).
The bozos at my dyno place printed everything but what I wanted...
Download here: DynoJet Run Viewer
11-29-2003, 03:07 PM
#26
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The beginning of the curve may be steep but the bulk of the curve is flat. Take a look at the "Dyno Battle" post. John's 4.5l twin turbo is making 300rwhp at 3500rpms. Only the stroker motor beats it at 3500rpm with 310rwhp.
I'm very impressed John.
366rwhp/.85= 430chp. (your car is a 5 speed right)
Nearly double the stock HP on only 11-12psi!
Andy K
I'm very impressed John.
366rwhp/.85= 430chp. (your car is a 5 speed right)
Nearly double the stock HP on only 11-12psi!
Andy K
11-29-2003, 03:46 PM
#28
Nordschleife Master
Thats pretty cool.
Looks like you could use a diffrent cam though.
Maybe off a US 78-79? Not much overlap, but longer duration for the valves. That would be good, right?
Looks like you could use a diffrent cam though.
Maybe off a US 78-79? Not much overlap, but longer duration for the valves. That would be good, right?
11-29-2003, 05:04 PM
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Shane, thanks for posting...
Yes, the thought of different cams has crossed my mind to hold that power out there a little longer...
Remember, those numbers are at somewhere between 11 and 12 lbs at the manifold. I had the car out today and saw 13.5-14 psig sustained in 4th gear. Hard to believe but the road loads the car harder than the Dynojet. Maybe an additional 10-15 HP, but I am not going to speculate and say it is or isn't there. Who cares anyway, the car is fast enough.
The torque is a little down below 3000 RPM because the mixture is still rich there. You can't significantly feel it, but I know it is because the fuel ratio was measured during the runs. I was fat rolling in the door and we shaved quite a bit of signal out of it to lean it up. I am still employing the Microfueler injectors, but very mildly. 95% of the fueling is done at the 8 ports without the use of a rising rate regulator....remember, I basically recalibrated the entire fuel curve with the MAF signal conditioner. The two additional injectors may be helping somewhat with charge cooling so they are staying.
Yes, it is a fun car. Honestly, it has enough HP for the street, specifically considering the brakes, suspension and tires. 5 spd, of course.... but even the limited slip has difficulties keeping it hooked up on 225s. I can ease it into 2nd at about 40, drop the hammer and it will break the rear out....you have to be careful coming out of the corners when the boost is cranked up.
I will probably run it mostly around 11 lbs for normal driving. The car accellerates so quickly, I normally won't see above 11 lbs until 3rd gear anyway.
It is nice to finally drive the car and not be watching the laptop or voltage meter....much safer for sure.
Now, if I can just manage to LEAVE IT ALONE and enjoy it. Is that possible?
To those who doubted me....let this be a lesson in the following:
Sound Engineering...first and foremost of course!
Sound Fabrication
Lots of Time
Lots of Patience
A bit of money
Sticking to a goal you know is real!
Yes, the thought of different cams has crossed my mind to hold that power out there a little longer...
Remember, those numbers are at somewhere between 11 and 12 lbs at the manifold. I had the car out today and saw 13.5-14 psig sustained in 4th gear. Hard to believe but the road loads the car harder than the Dynojet. Maybe an additional 10-15 HP, but I am not going to speculate and say it is or isn't there. Who cares anyway, the car is fast enough.
The torque is a little down below 3000 RPM because the mixture is still rich there. You can't significantly feel it, but I know it is because the fuel ratio was measured during the runs. I was fat rolling in the door and we shaved quite a bit of signal out of it to lean it up. I am still employing the Microfueler injectors, but very mildly. 95% of the fueling is done at the 8 ports without the use of a rising rate regulator....remember, I basically recalibrated the entire fuel curve with the MAF signal conditioner. The two additional injectors may be helping somewhat with charge cooling so they are staying.
Yes, it is a fun car. Honestly, it has enough HP for the street, specifically considering the brakes, suspension and tires. 5 spd, of course.... but even the limited slip has difficulties keeping it hooked up on 225s. I can ease it into 2nd at about 40, drop the hammer and it will break the rear out....you have to be careful coming out of the corners when the boost is cranked up.
I will probably run it mostly around 11 lbs for normal driving. The car accellerates so quickly, I normally won't see above 11 lbs until 3rd gear anyway.
It is nice to finally drive the car and not be watching the laptop or voltage meter....much safer for sure.
Now, if I can just manage to LEAVE IT ALONE and enjoy it. Is that possible?
To those who doubted me....let this be a lesson in the following:
Sound Engineering...first and foremost of course!
Sound Fabrication
Lots of Time
Lots of Patience
A bit of money
Sticking to a goal you know is real!