Heirsh

Any of you know anything about a whipple supercharger? In one of my books lying around a 964 was supercharged using one of these and raced.

Be gentle. I know only basic theory from my old school texts on supercharging as it related to my ic engine class.

Red rooster

Colin,
We got to see the World cup a bit later than you ( recorded ) so I spent Sunday morning avoiding all news programmes !!!!!!!!!!! Really good final with the result I wanted ( Sorry if that offends anyone ) .
I am not completely happy with the TPC method of using a 7th injector to supply the extra fuel . Looks like a fuel distribution problem waiting to happen .
I know they did that to keep US emmision people happy by leaving the part load operation completely standard .
A set of bigger injectors and a DME re map would be better ?

All the best

Geoff

NineMeister

Except that the 7th injector is also contributing to the cooling of the intake charge, and from my experience runs sufficiently rich under full load to ensure that fuel distribution accuracy (cylinder to cylinder) is not an issue. I believe that Geoffrey adopted your suggestion on a recent project and underestimated the cooling effect the 7th injector contributed into the system, I believe that this oversight caused problems with the engine.

That said, I have also fitted Motec onto a TPC supercharged RS with larger injectors and had a lot of success with it, but I made darn sure that the mixture was at least La 0.80 under full load and was very gentle on the ignition map.


Final comment is that for anyone serious about supercharging at high pressure with a whipple or similar is that you will have to modify the engine once the bmep exceeds the scope of a well tuned stock engine, i.e. machine the pistons to drop the compression and allow more space for the larger volume of charged air to burn.

Red rooster

Colin,
Thanks for that . Certainly makes sense !
All the best for the future

Bye

Geoff

jeff522

Didn't some one on the site drop the black box and 7th injector, and install an intercooler, or was that what Geoffrey did.I have been told that under low boost(3 psi) the stock program will deliver enough fuel to maintain a proper A/F ratio .Dose anyone know if this is true or not.Running an Eaton M-90 supercharger at low boost with an air to water inercooler would be a lot like the TPC system at a much lower cost. You would need to have skill or know some one to construct mounting hardware, ect. For some one with the skill it could be a good winter project.

Geoffrey

I was the one who installed larger injectors, dropped the Motronics and TPC black box but used the low boost pully (6psi). In fact, this was how I met Colin. The compression ratio was stock and I tuned the engine to a .84 lambda and minimum timing best torque and as the intake temps increased to aover 160F the engine detonated and I broke most of the rings. We then dropped the compression down to 9:1, same boost and retuned it as before. We ran it on the track and the driver ignored the warning alarm for AT and the engine detonated and broke the pistons and rings when the intake air temp reached 230F. We added the TPC intercooler, rebuilt the engine same specs, retuned it to .80 lambda. I held the engine on the dyno at full throttle at 4500rpm for 1:45 minutes and the intake air temps seemed Ok. Tested it again at the track on a 95 degree day and the intake air temps reached 160 after about 7 laps so the project scrapped. The engine was returned to stock Motronics with 7th injector and higher boost pully and has been tracked and been running fine since.

The shop I've worked with has the TPC kits installed on about 10 street/track cars with no issues. The only difference between what we were trying with the MoTeC and the Motronics with the TPC box is the 7th injector and knock control. I wish I had more time figure it out, but that was not the case and it was a frustrating experience and is the only engine I've had come apart due to tuning.