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Tom Drake's Opel GT to have fuel injection for the Runoffs

5027 Views 36 Replies 9 Participants Last post by  davegt27
I just got off the phone with Tom Drake, noted Opel GT racer, and he finally got a chance to fire his GT-4 Opel GT with his new fuel injection system, and run it on a chassis dyno. The good news is, the car makes more power than before, with an extended power band, and has far better low rpm tractibility. In fact, Tom says the car now idles smoothly at 1000 rpms, where it used to idle rough at 2000 rpms.

Tom is running a basic SDS (Simple Digital Systems) programmable fuel injection system, with 45 mm TWM throttle bodies. With the previous carburetors, the intake tract was restricted by the venturi size (41mm), but with the 45 mm throttle bodies, there is no restriction, only a smooth 45 mm bore. That, plus the superior atomization of the fuel injectors versus a carburetor, and the car picked up an appreciable gain in power throughout the rpm range.

For those who want to witness Tom in action, he will be at the Mid-Ohio Sports Car Course for the SCCA National Runoffs, which is being held from September 15th-21st.

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Stephen, that would be a very viable alternative, and in fact is essentially what I'm doing for my turbo Ascona wagon.

You could use a stock 1975 FI manifold, but with upgraded injectors (stock are NOT capable of feeding enough fuel). Get a higher volume fuel pump, and eliminate the stock cold-start injector, it's not needed with the stand-alone ECU. You will also gain airflow with the elimination of the air flow meter, so that's an added benefit. All you need to do is make an exhaust manifold for the turbo, add an intercooler (highly recommended if you're gonna use pump gas), and then bend up the 'plumbing'.

BTW, If we deviate any more from this thread, we should start another in the appropriate forum....

were the new rules open to all racer in this class or just the opels
because it seems like it makes so much more of a difference in power to the restrictive carbs

Any word from the RunOffs? I see Tom is 30 secs off the leader and no time from Stan in todays practice.... :(

Well, looking at the lap times, it must be raining like hell. Normal GT-4 times are 1:38 to 1:41 or so. I suspect Tom went out with dry or intermediate tires, and didn't push hard...it's only practice. No use balling the car up on day one!

Stan went to GT-4 earlier this year. Don't know why he didn't finish the practice session.

Stans move makes since the FP cars are as fast as GT4

i your not to worried about tube frame then it might even be cheaper to run GT 4

of course someone E-mailed me last year and said unless your dynoing 7 motors in the off season you can forget about GT4

did not know what to say after that

I see Bill Davidson is up there did he move back to Opels or did he stay with his Ford?

Bill Davidson has really developed his Fiesta a lot. If it rains, I expect him to win on race day, he can really drive, and that car seems well suited for the wet.

I don't know if/when Bill will return to Opels. I guess it really depends on whether or not they combine GT-4 and GT-5....the national participation numbers are really low and they are in danger of being dropped or combined into one class. If that happens, you can count on the Opels having weight added or the engines restricted more. But in terms of parts, Bill has more than enough parts to build a nationally competitive Opel GT.

I see it must have been dry out today at the Runoffs, I just went to the live update and the cars are flying this year!

The qualifying leader for GT-4 turned a 1:35.615 fast lap time. Tom Drake was 11th with a best time of 1:39.762, and finished 4.147 seconds behind the leader.
Bill Davidson turned a best of 1:40.439 and finished in 12th right behind Tom.
Stan Czacki must've sorted his car out from yesterday, as he completed the session in 17th spot, and turned a quickest lap time of 1:43.062.
There were 23 cars that finished today's qualifying session.

I had hoped for better positions for the Opel drivers, but hey, qualifying ain't racing!

I see john Mills is in GT3 whats he racing this year?
davegt27 said:
I see john Mills is in GT3 whats he racing this year?
He bought a Mazda RX-3.
why would he do a thing like that

an RX3 wow!
Faster car and class. Parts availability. Contingency money. Happens to work at a Mazda dealership.

oh ok seems like his Manta was moving up every year in GT4

6 place last year right

oh well
Looks like Stan was 11th and Tom 25th(down by 13 laps) in the race today. Hmmmm, maybe something broke?

It lists Tom as a 'DNF', so it appears something let go. I'll have to wait until he gets back to Vermont to call him and get the full story.

Interesting that they don't list the DNFs in the Java applet. I see it now in the standard results.

any report on the GT4 race and what happened to Tom and Stan

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