1988 Twin Turbo Dyno Results - 5 liter - 825hp/755tq at the rear wheels
#47
#48
Three Wheelin'
The 928 CVs are the largest commonly available. This is the size that you want to have when your big power non-928 starts breaking things. These are the 108mm CVs commonly referred to when big power is planned. They are often called "Porsche 930 CVs" but they are the same 108mm size.
Actual OEM Porsche 928 CVs have been the only part that hasn't been breaking on the big power 928s out there. My own has broken 2 trans among other things but NOT any CVs.
I have broken CV joints in other cars but NOT a 928.
Actual OEM Porsche 928 CVs have been the only part that hasn't been breaking on the big power 928s out there. My own has broken 2 trans among other things but NOT any CVs.
I have broken CV joints in other cars but NOT a 928.
#49
Man of many SIGs
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The Dyno run was made on E85, it is a flex fuel car, there is a flex fuel senser input to the Autronic SM4 and it will ajust fuel,boost,ing maps, based on % of ethanal.This dyno run it was 72% ethanal-28% gas. Bump in HP chart I think may be tork converter slip,so we stoped tuning, Luke Stubbs tuner of this car thinks,27-28psi boost could make 900+ HP. Intake has no floppy valve.
#50
Do you know which sensor you are using? Was it a Siemens YL5A-9C044-AA ? Are you using a dual return line on this car? The reason I ask is that as far as I know, this sensor is to be installed on the return side. The volume of fuel you need to push 800+ HP on E85 is immense and this sensor only has a #6 inlet. I would think that it would possibly act as a restriction if it was the only return path to tank and cause pressure creep. Sorry for all the questions but I'm in the process of building a flex fuel turbo 928. Nothing as extreme as what you built but Im eager to learn from others experience so that I don't unecessarily replicate a problem that someone else has already solved. Thanks
http://www.zeitronix.com/order/order.htm
I am not sure when Todd will chime in again, so I thought I would try and post some info. The readily available sensor is in many Dodge and GM vehicles. If you don't NEED to see the percentage, you don't need the meter - it can just feed into the ECU.
I do not know if ALL return is going though this.
#51
When we started installing V8's in the 944, the CV's, especially the inner driver's side would regularly explode. We found that a trans brace fixed that because the trans would shift towards that side and twist under the V8 torque. 930 CV's are some of the strongest CV's but would fall victim to this same problem.
#52
The Parts Whisperer
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Here is my .02 on axles and cv joints.
My 928 with 575 hp and 450 ft lbs of torque has NEVER had an axle fail or even wear out.
My cup car has almost 1/2 the hp and 1/2 the torque and it spits them out like bad gum. The difference is the plane in which they operate. The 928 is ideal or close to it.
My 928 with 575 hp and 450 ft lbs of torque has NEVER had an axle fail or even wear out.
My cup car has almost 1/2 the hp and 1/2 the torque and it spits them out like bad gum. The difference is the plane in which they operate. The 928 is ideal or close to it.
#53
Chronic Tool Dropper
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Engine needs to be further forward, with driveshafts behind instead of forward of the main oil sump. Then CVs would stay in better alignment as load changes. Note that above comments on orientation assume that the rear bumper arrives after the front bumper.
#54
Three Wheelin'
My really, really last bit on the CVs...
The "other" car I broke one on was a Cobra and it had alot of angularity.
The one that broke was a Chinese EMPI and it did so because the oval slots in the cage were not oval but tapered near the end in such a way that the ball forced it apart.
If either the CV was not poorly made or at such an angle it may never have happened.
The 928 does have the axles positioned well and in 1981(?) and later the trans mounting moved it even closer to zero degrees. The design of the 928 diff and crossmember does a great job of keeping the center of the diff in a deirable place. It's one of the details that make this a very good car.
The "other" car I broke one on was a Cobra and it had alot of angularity.
The one that broke was a Chinese EMPI and it did so because the oval slots in the cage were not oval but tapered near the end in such a way that the ball forced it apart.
If either the CV was not poorly made or at such an angle it may never have happened.
The 928 does have the axles positioned well and in 1981(?) and later the trans mounting moved it even closer to zero degrees. The design of the 928 diff and crossmember does a great job of keeping the center of the diff in a deirable place. It's one of the details that make this a very good car.
#55
#60
Three Wheelin'
Is anyone else trying to figure out which body parts to sell to have this done on their car?
Maybe I just need to move to GB.
Maybe I just need to move to GB.