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.

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.

I hear ya' JP. I'm still allowed 38mm chokes, since I'm in EP, but, get this, so is the 6 cylinder 914

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

I think NASCAR has it right. Don't put the racers in charge of the rules.

Keep it coming!

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.

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.

Dale,

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

brant

Yeah, I'm making the same leap. My 915 is out of a SC. I'm gonna go with the WEVO tailhousing... and Guard LSD.... 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...

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

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

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

Damn, Eric... didn't mean to piss in your cornflakes, but I did see your video 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.

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.

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.

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

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

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

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.

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


B

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.

Kevin,

We both know all you need to be competitive is the motor. Your chassis handles as well or better than what I have. Faster than me, you mean faster than Finch, cause he is building one. I know he has 95mm cylinders Nickies. He's coming, and he will win if he goes racing.

As far as the Hewland, I don't think you can use a MK style gearbox like I have with a good 2.7 liter engine. It just won't last. Even with Mk 5 gears, whoch does add a degree of reliability. You will need an LD 200 or the like to get what you need for that car. As far as having 15,000 in gearsets, SELL THEM, if they are worth 15k, you can have one helluva trans for that amount of money,

My MK 8 has a standard case and standard MK 8-9 gears. Although I will recase the trans this year and REM finish all of my gearsets. I had no failures last year, and hope to continue with the good luck this year. The dog ring trans is worth every penny. I will not build a 914 racecar without one.

Erik

No shit huh? Finch building a 914. That is COOL.

Looks like I need to make a call to RonW. It may be time to play again.

Eric,

are you serious about be able to buy the pieces for under 8k? I can sell all of Ron's parts if needed (tranny) do they all have LSD's in them? Can I use the 901 LSD in the Hewland case?

Why cant I use Hewland guts in a 901 box?? I just need some pieces to try it.



B

This is the Hewland Jim Blakewell uses in his SCCA Purple GT2 914. This one handles the 6cyl engines no problem.






B

ok... this hewland talk has peaked my interest/

so they are sequential and you can fit them in VW and 901 cases?

minor hijack - where can i learn about these... just to build my knowledge base?

Finch may run the 914 he built in the late 70s... the same one that won FP last year. I hope he does. I want to run against him. I may lose horribly, but he's certainly one of the best.

The Hewland's we're discussing are not sequential, but they are dog ring engagement (no lift shifts) with straight-cut gears (greater efficiency). I was quoted ~$8.5k for a new Mk9 with Mk5 gears and a quaife from Taylor, but that was a few years ago. It's a real racing transmission for sure. In the beginning Hewland used VW cases to build his transmissions.... so they bolt up to our engines without an adapter plate.

Here's some information: Hewland Website

Thanks for the link Kevin. I emailed them to see what they would recommend for my application. They show the Mk9 with Mk5 gears to be good for 180 Lb. torque. Would this be at the rear wheel or flywheel? My car dyno's at 166 lb. at the rear wheel. Not sure how that would translate to the flywheel.

Drew,

As I understand it if you exceed the torque rating it reduces the service intervals on the trans. Hewland is based in the UK and will probably refer you to Taylor as they did to me.

Taylor is a very good company and my dealings with them have been excellent.



So, my 915 arrived yesterday... ebay purchase for $850 plus $125 for shipping, from an '85 Carrera. I took it all the way apart today and it looks like somebody drained the oil and then let is sit submerged in water. Everything is rusted to shit. I'm hoping I can at least salvage the gears and synchros. So much for saving $ in the near term for passing on the Hewland for now...................regret oozing in.......

BTW. Anyone know what spline is on the 915 trans? Looks like 20 splines.

dude.. you got hosed on shipping depending on where it came from...

i was parting out trannies for a while and was getting them coast to coast for 40-60 bucks via UPS ground and cheaper by gayhound...

10 bucks for a rubbermaid tub and some foam, and some packing tape. DONE.

one dumbass shipped it to me with oil in it... UPS guy hated me LOLOL

You're right... but I think I got hosed on more than just shipping.

i didnt want to rub it in

but shipping is easy

thanks for the reading material on the hewland kevin!

If you need I can check a couple of places here in town.

There is a ld 200 on ebay right now. As far as the FP/EP cars the MK8/9 will work just fine. You can have one of these brand new from Taylor still for around 8500 with a quaife LSD. This WILL handle anything that an EP or FP engine can throw at it.

Blakewells 914-6 GT 2 car has an LD200 in it.

As far as the servicing on these gearboxes. I run Ceramic bearings in the tran with swepco gear lube. And have had zero issues. The LSD I have no one seems to know what it is, so I can't tell you myself. I can provide photos of my install to anyone that may be interested. I really feel it is worth it.

Erik

So, I fully disassembled this trans and used the wire wheel on the gear teeth..... pitting from rust.

Certainly all the bearings were toast, but all of the gears are too. So, all I got was a dirty trans case.

I e-mailed the seller and he offered to refund my cash

So, I'm going to box up the parts and send them back to him.

My faith in humanity is restored!


Now I need to revisit my trans decision since having this case showed me that the 915 clutch lever interferes with the Tangerine header.

Might just throw a 901 back (with a new ring and pinion) in it for another season, then move to the Hewland later.

Kevin,

To run the 915 in a 914, you flip the arm around and make it stick out the drivers side. I "think" this will clear the Tangerine header.

Erik,

can you post the pics of your install. I have seen several of them, but you may have more.

B

I never received an answer to my e-mail to Hewland. Not a good sign. I've pretty much decided to fix my 901 and save my money for a Boxster. I wanna be like Bill!

That is too funny Andy!!

I wanna be like BILL!!

Let me know! You know full well I'll be right there helping you strip one and get all the suspension under it. We can do it in a weekend with the right tools!!

You'll have to feed me and give me a place to sleep..LOL


B

Andy,

Try Scott at Taylor scotty@taylor-race.com.



Brad,

I now what you're saying, but I'm actually worried about the vertical shaft that pivots the throwout bearing, so flipping the lever wouldn't get me out of that problem. It my fit, but it would be close.

We typically run hydraulic throw out bearings in the 915's.. havent had to deal with the clutch arm!

Erik..... pics ????



B

Do you know one that fits? My discussions with Taylor said it was tight and the 915 looks like it had less room than the 901.

I'll try to post, but some asshole reduced the size of pics that you can post here, or maybe my new camera is just TOOOOOOOOOOOO PHAT.
I am too stupid to understand how to reduce a pic size to be uploadable.

This should be a shot of the mounting plate:

I had this plate CNC'd to put the alignment step in both sides. One protrudes, one is recessed just like a porsche engine case.

The engine AND transmission mounts from these two holes in double sheer.

Click to view attachment

This is the engine and trans attachment plate. It has the proper protrusion and indetation step to center the engine and trans. I had shop CNC this for me.

The rear of the engine and the entire transmission is supported by this plate and the two mounting bolts that are in double sheer. The bolts are 10mm


Erik

Click to view attachment

This is the front side of the same mount. This is the engine side. The crossbar is welded to the chassis spars left to right. I haven't completed it, but this was an area, I thought I could trangulate the chassis a bit.

Erik

Eric,

Looks to me (but I might be blind, 'cause I'm looking at the Taylor catalog exploded views of the Hewland) that the Hewland is built with the pinion shaft on top of the mainshaft...... unlike the 901. Did you install yours this way or did you flip the ring and install it like the 901?

Click to view attachment

This is mostly of the exhuast, but the detail of the bushing and the shift rod mount is pretty good, This is just a simple delrin bushing , just like the one that goes through the firewall. With a circlip on each side, it can be changed easily, and two bolts remove it from the mounting plate when removing the engine/trans from the car.

Erik

Click to view attachment

This the transmission I am using It was an aircooled Supervee. This linkage is refered to as "Monkey Motion", but I have found it works very well. The early formula Mazda linkage is basically in the same sport, just a little bit forward of where my linkage is on the trans.

Erik

Click to view attachment

I took this to show where the linkage comes through the firewall.Again, I use a very easy to make delrin bushing. The firewall has a drilled hole in it. And the bushing gets a touch of grease to make it slide, or KY, whichever I have laying around in 55 gal drums

I have a friend that is installing a 911 5-spd trans into his 914, He is turning it upside down, added oil flow ports an pump for circulation and other stuff, I will get more info, but have you guys ever heard of doing that type of thing, he races his 914/6 all the time and wins with it,, I will add photo's later,, if interested...

Click to view attachment

here is a shot of the entire shift rod.

Click to view attachment

Another shot of the crossbar added to the back of the engine bay. Again, I plan to triangulate this area this winter, but this is where the engine and trans hang from, Well theres a front mount too, but the trans hangs from this mount, there is no rear trans mount as with the 901. I did this so I could change trans gears with limited issues. I just need to disconnect the shift linkage, and loosen the front engine mount, remove the two engine mounting bolts. All of this takes about 4 minutes. Drop the engine down about 3 inches and out comes the entire gearset. it take about 30-45 minutes to change th entire gearstack. When I am hustling.

Erik

Click to view attachment

This is the shift linkage I fabricated. This was one of the most difficult things to do. It is very close to being perfect, but I am going to try some different fore/aft ratios. The linkage is really good. I am using 5/8 APEX joints and welding them wherever possible. This eliminates the apex connection from moving around. if you use AOEX joint for anything, do these couple things. Out a steel slug in the tube they are clamping around, This will prevent the tube from collapsing when the bolts are tightened. Use a fixture when drilling them, and use half moon washers to spread the load out. I used 5/8 chro moly tubing .083 wall for the shift linkage from aircraft spruce. the box is hand fabbed from aluminum, welded by CFR welding, it has delrin bushings front and rear, and uses heim rod ends to control for aft motion of the shift lever.

Erik