Subaru Transmission into 914, DAMN that turned out good!! Options

[DBCooper]

They say the front end pushes badly at low speeds, and, surprise surprise, the back end goes liquid under power.

This car has a Quaife limited slip dif, eh? I wonder if the limited slip and power-on while entering the turn and/or during decel is the cause of understeer. Could this be resolved by changing the driving style a bit? I am very interested in this issue, as I've installed an OBX LSD in my Suby trans...

That's the likely explanation. I had some of the push before and I'd already gotten those 7 inch wheels as part of the cure. We'll see what that does and go from there, but the message after the autocross was that we're going to need to learn to drive the car differently and especially use the accelerator more in steering.

It's not a big deal, it was the first time out to see where we were, a shake down and learning experience. The engine and transmission are in and good, so from now on it's going to be fun sorting the new car out. I'm not nearly as interested in how it does at autocrossing as I am how it does in the hills, but autocrossing is perfect for the sorting and learning how to drive it without ending up in the weeds.


.

[budman5201]

Looks excellent....be careful coming out of corners with your foot in it. Boost, small tires and turns can equal snap oversteer and a weedy experience.....

Yes but thats the kind of turn exit we all love!

[Andyrew]

As part of their destructive testing program the kids took the car to a PCA autocross in Stockton.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i255.photobucket.com-2618-1269561145.1.jpg)

Good news is that they didn't break anything. Bad news is that we're back at square one for suspension setup. They say the front end pushes badly at low speeds, and, surprise surprise, the back end goes liquid under power. Their suggestion is flares and big stickies, but that isn't going to happen. All I want is a narrow-body sleeper. So it looks like bigger 7 inch wheels on the front (it's now 6's and 7's) and learning how to drive it differently, moderating the power a little better. Then we'll tweak as we go along.

All in all it's great, a total success and a helluva lot of fun to drive.

I was debating going to this event!!! AHHHHH!!! Would have loved to see this car in action.


What are your rear spring rates? Front Tbar and sway bar size?


You know one of the things that My dad did on his highly modified 944 turbo is switch to really sticky hoosiers on the front and old hoosiers on the back, Wider in the front. The car previously had really bad understeer, now its is so neutral its not funny, and so controllible to drift! When me and him swapped cars at a autox school I had SOO much fun drifting the whole course.

Also tire pressures play a big part.. Is your front sway bar adjustable? Lemme know, I'd love to help you guys out setup that car!

[DBCooper]

I think rear springs are 140, Koni adjustables on full soft, no sway bar. Front struts are stock Carrera Boge inserts, stock 914 torsion bars, Tarrett sway on softest. Falken Azenis, I think 205-50-16, 7 inch rear, 6 inch front. I don't know tire pressures. They just got the car running, so I think they just drove it up without time to look at much. They didn't bring an air tank, and even forgot to bring the Koni adjuster.

There are videos of all five runs HERE.

This is the fastest of the day:

https://www.youtube.com/watch?v=yor2_4Acqlo


They were playing with brake balance during the day, and the first runs locked the front up some. The last runs (smooth and fastest in the videos) looked better. You can hear wheelspin down some straights on all runs, but the big sticker is the way they're just skating, limping around low-speed corners. My son said it was enormously frustrating, that it was so slow in corners, but just a touch more throttle and it would come unbalanced and plow straight. Really difficult to drive.

We suspect the front is too low and may be bottoming. They'll zip-tie the tops of the front before the next time out to see what suspension travel they have left, if any. The sway bar's adjustable, so we'll try that too, but I think the biggest improvement will probably be better rubber on the front with the 7 inch rims. Then it'll be 7 front and back, with full suspension travel and a little stiffer on the front sway bar.

They found out that the car's solid, which is what we were most interested in, now we just need to get it set up. This is the fun part, I think.

[d914]

I found from my track days that yes you steer with the gas rolling on..I found out that one on a cold moring trying to coast through a difficult corner..car was pushing wide while going slow..steering didnt work, brakes werent going to do it... rolled on the throttle and it bit and turned!!! the ah ha moment came... also as much track and tire upfront that you ca get.... I know this is vastly simpified but brake and shift in straight lines, roll on throttle going towards apex....I dont autocross but I did a fair amount of track work..

[roachghia70]

You can hear wheelspin down some straights on all runs, but the big sticker is the way they're just skating, limping around low-speed corners. My son said it was enormously frustrating, that it was so slow in corners, but just a touch more throttle and it would come unbalanced and plow straight. Really difficult to drive.


They found out that the car's solid, which is what we were most interested in, now we just need to get it set up. This is the fun part, I think.

I can't wait to take it out autocrossing again! We did play with tire pressures and brake bias, but it felt like fine-tuning something that needed bigger adjustments, if you know what I mean.

You said it, the car was just plowing no matter what we did. In the videos, you can see where we were trying different things to try and get the rear end to turn, but it just wouldn't do it. Sudden off-throttle while jerking the steering wheel didn't even do it. I was literally TRYING to spin the car off-throttle but i couldn't. In the end, what worked best was braking harder before the corners, then holding it at about 1/4 throttle through the turn, just like d914 said in the previous post.

There's one other thing to keep in mind here though. There are lots of things we could do to the car to make it much faster in autocross, but that's not really the point of the build. It's really just supposed to be a fast, fun, comfortable and SAFE car to have fun with on mountain roads and on track days. And it does that beautifully. If we stiffened the rear suspension, added a sway bar in the back, added some camber up front, bigger stickier tires, etc... it wouldn't be as predictable and safe to drive on mountain roads. I'd rather have a car that will not ever oversteer (until you ram down on the throttle) than a car that could come around backwards if you're not careful with your driving.

So at this point, I think we should figure out if it is bottoming out on the front and fix that if it's true. And maybe a couple of other things, but I don't think we should go too crazy with adding too much oversteer to the way the car handles. I want to autocross it again with the rear Konis set to full stiff, more braking force added to the rear, and try to change the driving style even more, like d914 described. And then just go from there.

That engine and tranny are just phenomenal though. It just feels like a modern version of a 914. It still acts like a 914 with the way it is nimble and low, but there's plenty of smooth power, and there's no concerns whatsoever with the drivetrain. And downshifts are no longer necessary to pass people on the freeway! haha The car is just awesome to drive.

[Andyrew]

The point of the car is to have it neutral at most speeds, However its very apparent that you need some more front grip. Check the tires pressures and report back, I'd say start at 25 front and rear and work up from there. Even swapping the front tires to the back to give you the bigger stick up front might just make it handle that much better. Let me know next time you take it for an autox, I'd love to see if I can help you guys out make it a more balanced car! A rear sway bar might not be a bad investment, Its very easy to disconnect a linkage and reconnect a linkage if you decide that autox is the thing for you.

When I built my Audi I built it to be a really balanced car and one of the most important things I did was add a really big rear sway bar, This gave the car so much balance I could toss it in any corner and make it do pretty much what I wanted. I've had it at the track and at the autox with the same setup and it simply worked amazing (1.04G's on street tires). I know exactly what you guys are talking about when you want to have a car that is just comfortable fast and safe.

Looks Car looks great out on the autox BTW!

Andrew

[DBCooper]

Hey Thomas, welcome! That's my son, the Industrial Designer and our destructive testing guru. Kid has skills, and is a hot shoe who usually has FTOD in our group.

Thanks, Andyrew. This was literally the first time it was on the road after all the work that was done, with huge changes made to every part of the car. The autocross was just a quick way to see what we had and where we were. The results aren't posted yet, but even with no setup work done their times will probably be pretty good among the cars that were there, and not bad at all for a brand new car. Jeff, the guy who did the work, among other things was crew chief for the Spoon USTCC series Evo that won the national championship, so has a good racing background. He has setup suggestions we'll be trying, and he's really good.

What we wanted to do most of all was prove the engine/transmission combination, and we did. Not one hiccup, but unfortunately it looks like the whole day was spent in second gear. I'm sure the kids would be happy to let you know about the next autocross, but don't know that there'll be another. I don't really want an autocross car, so we'll be aiming at generally neutral at higher speeds in the canyons and for track days, but not so much lower speed autocrossing. So if they do go out again it will be just for fun.

[Joe Bob]

2nd gear? Welcome to AX.....I haven't seen 3rd since I quit going to San Diego. You won't see 4th until you graduate to Driver's Ed events.....

[KaptKaos]

Nice build.

Which axles are those?

With all that power, you should get flares in the back. I am not sure how many here remember BJ (Crazyhippy). He had a WRX motor in a narrow car, and tweaked it good. Thankfully he wasn't hurt, but he had the boost turned up high! Even stock 230+ HP is a lot for these little cars.

Nice build, keep posting!

[Porcharu]

I am pretty sure those are stock VW buss (100mm CV's) axles the flanges are the ones I made for the group buys.

[ruby914]

WOW!
Fantastic job.
Makes me want to grind out all my welds and start over.
Now, I can look forward to the day my Porsche transaxle disintegrates.
Thanks for rewriting the manual.

[Rod]

Amazing subaru build! One of the best if not the best engineering wise I have ever seen.. If your man at 1340 wants to offer a kit to a WRX wannabe in the UK let me know (IMG:style_emoticons/default/wink.gif)

[jimkelly]

one of my all-time favorites.

can you break down the cost.

engine/trans?

all fab, material, labor (ballpark) ?

misc?

thanks
jim

[badmiata]

Many question! What yr sti did you pick and why? Does your stand alone ecu make everything work ( sti heads/valves). Does it have an immobilizer? Could would have used the stock ecu? Does the wrx trans control the speedo? I got a say that this is perfectly what I want. Now I just gotta get the money!

[Chris Pincetich]

Sweetness. Great to see the newest thinking in the Suby conversions, which is in my opinion, the best option for 914 IC engine conversions. (IMG:style_emoticons/default/beerchug.gif)

I have missed way too many AX races this year...started strong and now off track due to lots of work. Honestly, if you set up your 914 for the best AX time, you loose that road safety factor. Understeer in the mountains is way safer than too much oversteer! With all that juice, creating throttle oversteer should not be a problem.
(IMG:style_emoticons/default/driving.gif)

[Chris Pincetich]

woops, double post, delete me
this website never loads my posts right

[Chris Pincetich]

I want one

[DBCooper]

Sorry I haven't been around lately, lots of things have happened. Got downsized, started a new company, got it off the ground and then almost immediately wadded up a new motorcycle. Am still recovering, one of those life gets in the way things. I've been getting a lot of personal messages about the build. I've tried to respond to all but probably haven't done it quickly or well. Sorry, been really busy.

As a progress update I don't expect to be in California as often in the future so drove the car back to Texas. No drama, the thing's excellent on the superslab. Hot, humid, and not as many curves in the roads back here, so need to finish the A/C. Bummer. We went through the Falken Azenis so now into some Kumho Ecsta XS's, hoping for a little more DOT grip. Don't want to flare it.

I don't know what else to say. It just runs, runs great, and you can't seem beat it hard enough to make it notice. I was pretty sure my kids would find its limits, but they didn't, and that's from a $600 Craigslist motor. And that may be the coolest thing. It's not an antique, so if I ever break this sucker I know there are cheap and easy replacements nearby. I was keeping an eye out for an STI motor to put in the corner of the garage as a spare, but don't really see the need any more.

Anyway let me know if I can tell you anything else, or help in any way.

[sawtooth]

Paul sure sorry to hear about your crash, hopefully not too serious. I hope your recovery is quick and you can get on with life. You've been a huge help to me and my project and provided some fantastic 914-suby inspiration. Look forward to seeing some more videos in the future!

Sorry I haven't been around lately, lots of things have happened. Got downsized, started a new company, got it off the ground and then almost immediately wadded up a new motorcycle. Am still recovering, one of those life gets in the way things. I've been getting a lot of personal messages about the build. I've tried to respond to all but probably haven't done it quickly or well. Sorry, been really busy.

As a progress update I don't expect to be in California as often in the future so drove the car back to Texas. No drama, the thing's excellent on the superslab. Hot, humid, and not as many curves in the roads back here, so need to finish the A/C. Bummer. We went through the Falken Azenis so now into some Kumho Ecsta XS's, hoping for a little more DOT grip. Don't want to flare it.

I don't know what else to say. It just runs, runs great, and you can't seem beat it hard enough to make it notice. I was pretty sure my kids would find its limits, but they didn't, and that's from a $600 Craigslist motor. And that may be the coolest thing. It's not an antique, so if I ever break this sucker I know there are cheap and easy replacements nearby. I was keeping an eye out for an STI motor to put in the corner of the garage as a spare, but don't really see the need any more.

Anyway let me know if I can tell you anything else, or help in any way.