Turbo-4 '89 Mustang roadrace coupe.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

[mike343sharpstick]

Re: Turbo-4 '89 Mustang roadrace coupe.

Awesome! Congrats on burnin' some fuel.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

Redid the numbers on sizing the fuel pump, we may have been pushing its limits when we changed to E85. Old pump was 67 Gph free flow, new pump will be 110gph fee flow. It should flow right at 70 gph at our maximum 65psi fuel pressure. I can't find a voltage drop curve for it, so we'll keep an eye on it for a while.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

Got the pump, we thought it was set up for alcohol, but it looks like it needs a kit to convert. Damn. We'll order the kit.

Freakin LSx plug wires. We've been trying to match our plug wires, not LS1, not LS2...finally figured out they are LS6. 13" from end of plug to end of plug. I've got a set of MSD 8.5 wires with the proper spark plug ends, ordered a set of 45* ends for the coils from Summit, should get here tomorrow.

We hope to have everything plumbed and wired on Saturday and run it up and down my buddy Scott's private drive. I hope we don't piss off all the neighbors. If things work, we'll go to an autocross on the 10th and see if it runs.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

Looks like we'll make it for this weekend. Plug wires are made up and installed. I've got to make-up one bleedline for the pump to help it prime. Scott made up a mounting plate, he's off tomorrow and will get it installed.

He also talked to Mallory about the pump, they say its compatible with E85, so one more item off the list.

I've asked a buddy of ours, Lee, to drive on Saturday. He is a hard core autocrosser so he'll know what to do. I needed to remove a variable from the test (me, I've never autocrossed) so that we can determine what's up with the car. Hopefully the plug wires and pump will cure the issues and we'll be ready for another track test before the enduro race in May.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

I'm so freaking pissed. While trying to reclock the fuel pump to work with our plumbing I dropped the gerotor out of the pump. Now it grinds like crazy. Calling Mallory, they say we have to send it back in for them to resync the gerotor. That's beyond dumb on a rebuildable pump.

Looks like we'll miss this weekend.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

Got the new pump working, changed the fuel filter, it was causing the pump to cavitate. Put on the new plug wires. Damn thing still breaks up at 4,000 rpm on 10psi. However, I did notice (while riding on the floorboards watching the LM-1 show me AFRs) that the voltage in the system was only 12.2v. Not good. This thing hates low voltage. So, maybe we ate another alternator. ARRRRGGGGGHHH.

[seanm]

Re: Turbo-4 '89 Mustang roadrace coupe.

So close to perfection! Must be darn frustrating to be so close.

Have a question about the suspension on the front. Did the SLA system have longer arms to push the wheels out to the wider fenders or is wheel offset used to make the track wider?

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

Sean, you are so right!

The SLA does push the wheels out, but the big reason for the track width increase is the use of the Sweet Spindles and Howe hubs. The wheels have 7" of backspacing on a 9.5 inch wheel. The wheels for the front are custom. I had to have Stockton wheel fix the steel 16" and the CCWs were ordered with that backspacing.

[seanm]

Re: Turbo-4 '89 Mustang roadrace coupe.

Thanks for the info, have any close-ups of the front suspension?

How would adding negative offset to the rim affect the handling if you had used the stock spindle and hub? Does the aftermarket spindle and hub have the same effect as changing the offset of the rim?

Thanks

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.



I don't know how it would affect the stock spindle and hub as I didn't model it in the software. I went to the aftermarket spindle and hub because at the time Griggs could not supply the dropped spindle that was necessary to make the SLA work properly. I needed to use the 7" backspacing in order to keep within the track limits for the class and also to limit the scrub radius to something acceptable with a manual steering rack.

[mike343sharpstick]

Re: Turbo-4 '89 Mustang roadrace coupe.

Thanks for posting that pic, looking at the 'bones' of a car like this is very cool.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

Must be the damn alternator, Scott tried to start the car yesterday and not enough juice in the battery to turn it over. We're back to trying to match the proper pulley with the crank pulley. We use a 4" crank pulley and an oversized water pump pulley to underdrive the water pump. Looks like we'll go back to a 2.5" alternator pulley. We have a 6,000 rpm redline on the car so it should not overspeed the alternator.

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

Here's a slide show of some of the earliest work on the car:

[horsewidower]

Re: Turbo-4 '89 Mustang roadrace coupe.

WoooHoooo. Looks like we may have cured the problem finally.

We have a buddy, Tib, who has a 3200 foot long ag airstrip that he allowed us to use to test the car. We were dismayed to find that even after all the new parts we've thrown at the car, we still had the issue of it acting like it hit a rev limiter when it got to about 4,000 rpm and about 10psi boost. We had plumbed a fuel pressure gauge so that we could read it while driving the car and also wired in an AFR gauge that could be read by the driver. So we new we had enough fuel, if not a little fat, and we had enough air, getting to 10psi with no problem.

So it was time to go back to basics. Air, yep, Fuel, yep, Spark... Hmmmm.

I've had some back problems, so I wasn't driving. I asked the driver to run the car up to the problem area and then shut the car down and cost in so that I could read the plugs. 1, 2 were fine, 3 looked out of sorts, and 4 looked OK. Looking closely at #3, it had a cracked porcelain and we also swapped the coils on 2&3. The guys pulled out (we had a guy sitting on the passengers side helping to read the gauges) and it was immediately apparent that the problem had been cured. On the return run the passenger was holding onto the rollcage with both hands!! It revs like a chainsaw.

Sometimes its the simplest shit that kicks your ass. It sure feels great to finally get some clean runs on the road. The airstrip is longer than any straight here in Norcal so it should be a good indication that we have cured the issues. I can't wait to get in the car.