Going with the 915 trans, I'm taking the plunge Options

[groot]

I've researched it and decided to go for the 915 trans.

Due to job insecurity, I'm not comfortable buying a Hewland at this time. And since I'd need a replacement 901 case (or at least a ring and pinion-see "Pinion failure" thread) which would run me a few hundred bucks, I decided a few hundred more for the added strength of a 915 might be a good plan.

I scored an '84 Carrara 5-speed for <$1000. I will flip the ring myself and replace whatever else needs to be replaced over the next few weeks.

I have to decide whether I should add a cooler and pump or not....

For now, I will run the stock ratios. Check out this gear chart.... 2, 3 and 4 in the stock 915 box are remarkably close to what I was running in the 901 box. I only used 3, 4 and 5 with the 901. Knowing that Topeka has some very slow corners, I know I needed a lower 3rd (901), which 2nd in the 915 gets me. The purple box is an estimate from Jake about where the race engine will make good power.

As for the linkage... I've got a few ideas. I don't want to spend the $$$ for the WEVO setup, although it looks georgeous. If there's interest, I'll post progress pics.

[J P Stein]

This is "Production" racin', eh?
It would seem to me that the SCCA has really fucked up their rules. Who ever is in charge is an idiot....or a group of idiots. Sure, you can add a Hewland but no 36 mm chokes on them Webers...or some such absurdity. They prolly whine about the cost of racin' to boot.

[groot]

I hear ya' JP. I'm still allowed 38mm chokes, since I'm in EP, but, get this, so is the 6 cylinder 914 (IMG:style_emoticons/default/idea.gif)

I think the FP guys got their 36mm chokes, but not 38mm chokes.

[J P Stein]

I think NASCAR has it right. Don't put the racers in charge of the rules. (IMG:style_emoticons/default/biggrin.gif)

[Jeroen]

If there's interest, I'll post progress pics.

Keep it coming!
(IMG:style_emoticons/default/popcorn[1].gif)

[EMRoadster]

I've researched it and decided to go for the 915 trans.
<snip>
As for the linkage... I've got a few ideas. I don't want to spend the $$$ for the WEVO setup, although it looks georgeous. If there's interest, I'll post progress pics.

Kevin,
If for nothing more than reference, check out the cable shift settup that Renegade Hybrids in Las Vegas has. http://www.renegadehybrids.com
I was up there back in April this year and Scott (the owner) showed me one installed in a 914 with a 930 trans that felt like shifting a very nice top load conventional trans. I plan to get one for my 914 with a 915 trans when I get to that stage of the build.

[flesburg]

FYI:
Some of the 914 race car guys from Denver have fabricated home made shifters for their 915's that look good. They look relatively easy to fabricate and they do work well. Send a PM to my son, JOHNMAN. He has several pictures and would be willing to share them with you.

[brant]

Dale,

I'm pretty sure those are actually grand junction fabrications....

brant

[kdfoust]

Yeah, I'm making the same leap. My 915 is out of a SC. I'm gonna go with the WEVO tailhousing... (IMG:style_emoticons/default/chowtime.gif) and Guard LSD.... (IMG:style_emoticons/default/burnout.gif) I was just at my mechanic last week and saw that the main shaft bearing race was loose in the housing. Oh well, it's only money... (IMG:style_emoticons/default/beer3.gif)

I've been considering the trans cooler options. For now I'm going to roll it out with no cooler installed but I'm planning to monitor temps AND add some guarding (TBD) to keep the heat from the headers away from the transmission. What's best place to monitor tranny oil temp? I could install a TC in the drain plug but did Porsche have a factory location for the tranny temp?

Later,
Kevin

[Brad Roberts]

Kevin,

the 915 has a lot more air flow under the 914 than it does in its config in the 911. Porsche doesnt show a place to take the temp. Most people monitor the gear lube directly under the diff.

Ceramic coated headers will be enough to keep everything in check heat wise.



B

[Thorshammer]

Kevin,

38 MM chokes, Don't forget to mention these facts as well you goofball,

The 6 weighs 80lbs more per the scca rules, the -6 carries 70-85 lbs more over the rear half of the car. The 2.0 has a piss poor combustion chamber I don't think I need to continue. As soon as Finch waxes everyones ass next year in his EP 4 cyl, we are all fucked anyway. So you better get your engine done. Cause next year will be the final year for the 914.

As for the 915, you building a racecar or not. Why do a 915:

Its cheap, it's big, and strong, It takes some fabrication to install one, you know people that have installed one.

Why install a Hewland:

It shifts, right now (Dog ring vs synchromesh), GEarsets are cheap (most can be had for less than 100.00 (drive and driven gear), You can regear it at the track in under 1 hour. It takes some fabrication to install one, It weighs the same as a 901, The difference is amazing. it shifts like a real racecar, quick fast and in a hurry. It WILL be an advantage at Topeka if you go. It costs more, but not as much as you think. I have found them in good working order for about 2k. Thats pretty cheap. Oh, and you know people who have installed them.

Erik Madsen

[groot]

Damn, Eric... didn't mean to piss in your cornflakes, but I did see your video (IMG:style_emoticons/default/shocked[1].gif) Just harassin' you, buddy. 50% increase in choke area for 80 pounds. I'm pretty sure who has the advantage. But, I'm just a goofball.

I'd love to go with the Hewland, but I haven't found any of these bargain Hewlands and our job situations are very tenuous right now. My wife got a package (for voluntary separation) the other day and I'll get one in a few weeks. If it gets to the point where one of us gets asked to go, you won't see me at any tracks for quite a while as a driver.

I've also been warned about going with use Hewlands. Anyway, the point is to keep my car on the road, I'm going with the 915 and yes, it's a compromise.

[drew365]

(IMG:style_emoticons/default/hijacked.gif) Could I take a moment to ask about the Hewland? What model fits our 914's and is it cable shift or rod? My 901 needs to be opened up again, maybe this is a good time to look into alternates.

[groot]

Eric's got one installed.... I will eventually, but not for a while.

Most of the Mk series will fit... they use the VW case, so it bolts up to our engine. The Hewland is not a street-able solution, so only consider it if your car is track-only. As I understand it, a used unit from an early Formula Mazda is the easiest solution in terms of compatability. I don't know of an off-the-shelf solution for the shifter, so you're on your own there.... same with mounting it in vehicle.

[drew365]

Thanks, I'll do some searching and see if this is something I want to tackle while the car is down for body repair.

[Thorshammer]

Kevin,

Just kidding. You should give Heinricy a call. I amsure he could use some solid guys over at his place. As far as the venturi size, it works. I think the hot set up for the short run would be to run a four cylinder for the RUNOFFS, and the six for the rest of the year. The 2.0 four can be the dominant car. I really believe that.

Once the Kirby car gets sorted, it will all be over, and the CRB will be sticking it to us. BOHICA.

Erik

[Brad Roberts]

The MK wont work well with Andy's HP/torque. He is breaking 901's right now with a NICE 2.7 engine.

I did the math based on Data acq from a 901 tranny'd EP car at Laguna. The driver could be on the gas with a dog box for something like 1.8 more seconds if you added up the amount of time he was off the gas to make a 901 upshift around Laguna. He seriously considered the move when SCCA said "YES". The issue is: he has close to 15k in 901 gearsets and 3 ZF limited slips amongst 3 tranny's.



B

[groot]

I'm glad Kirby's coming, just like I'm glad Len and Jake are building a car. It will only force me to be better.

Eric, I do hope I can get to be as fast or faster than you.......that's definitely a goal of mine.

Brad, WOW!!! 1.8 seconds is a huge gain. BTW... I was told to use the MK5 gears for my horsepower. Scott Young at Taylor sent this to me, "The MK5 gears will give you an increase from 190 to 240HP.".... but I always thought gear strength was based on torque, but what do I know.

[Brad Roberts]

Who owns the Kirby car now? Or did she not sell it?


B

[groot]

Last I heard was that the Kirby family was is sticker shock when they got the bill from Finch.... and told Finch he could keep the car. That was second hand from a few months ago.

I spent a morning with Finch about a year ago and he was talking about going back to production with that car because he was so pissed about what was going on in GT. He wasn't sure whether he would go EP or FP. I did see that he had his GT 944 up for sale, but the price was insane.... perhaps it was just a statement. I did not run into him at the track this year.