SpeedFactory '09 Vitara D16 build - Page 11

Big Tuna · 07-12-2009, 11:31 PM

What size tires? and RPM shifts My z6 trans on 22's does 98ish mph at 8k, that thing looks like it does 130's in 3rd?

JFK78 · 07-13-2009, 12:15 AM

Originally Posted by Big Tuna

What size tires? and RPM shifts My z6 trans on 22's does 98ish mph at 8k, that thing looks like it does 130's in 3rd?

Seems crazy doesn't it? The tires are 24.5 x 8.5 x 15 M&H's. Rev limiter at 9500rpm.

These tires are definitely taller than the 24.5 x 8.5 x 13 M&H's I ran last year though judging by how much more they fill the wheel well.

Adding in tire growth I believe these are about 25.25" in dia. on the top end which works out to 134.3mph at 9500rpm in 3rd!

JFK78 · 07-13-2009, 12:19 AM

Everyone at the track was like "jeez, your 3rd gear is retarded long, did you even shift to 4th?" Yeah, right at the line!!

Last year on the other tranny I was crossing the line near the top of 4th, now on the stock tranny I'm just grabbing 4th.

I can't even recall if I've ever seen any video of another mid 10 second honda doing the 1/4 in 3 gears. Has anyone else?

turboy7 · 07-13-2009, 08:39 AM

Congrats on nearly beating last year's pb! Must feel great. What were your 60' foots with the stock trans?

mcr00ex · 07-13-2009, 09:07 AM

Originally Posted by JFK78

Everyone at the track was like "jeez, your 3rd gear is retarded long, did you even shift to 4th?" Yeah, right at the line!!

Last year on the other tranny I was crossing the line near the top of 4th, now on the stock tranny I'm just grabbing 4th.

I can't even recall if I've ever seen any video of another mid 10 second honda doing the 1/4 in 3 gears. Has anyone else?

I did a 15 second pass with a dx trans in 3rd.... haha

Big Tuna · 07-13-2009, 09:12 AM

Originally Posted by JFK78

Seems crazy doesn't it? The tires are 24.5 x 8.5 x 15 M&H's. Rev limiter at 9500rpm.

Lol that would explain it.

JFK78 · 07-26-2009, 12:23 AM

Well, bad news. The motor is done.

One of the pistons decided to leave the building. No abnormal combustion or anything like that, all cylinders and plugs are/were perfect until this pass. #4 piston just came apart at only 23-24psi at the track. The wristpin beating around in there cut grooves all down the cylinder and cracked the sleeve at all 4 contact points.

We either found the limits and pushed them too far, or it was a freak incident that 1 piston fell apart.

Here's what we found when we pulled the head:

On a good note, it stayed together long enough for me to get my NHRA competition license!

debow · 07-26-2009, 12:57 AM

that sucks so what the plan going to build another motor?

JFK78 · 07-26-2009, 01:16 AM

Well, now that the head is off the car, we can have it digitized and offer a great, proven Y8 head port job.

I already have another Z6 head being ported right now as well.

I don't think we are going to do another vitara build for my car though. It's time to step up to sleeved/forged for reliable power now and not having to worry about running it at 600+whp. We were going to go that route at first, but decided to try it with the vitaras instead.

We pushed the stock sleeve/vitara build to and way beyond all established limits and figured out how to build a good D16 combo that works well and makes great power, but at this point I would say that it's just not reliable enough for what we want to accomplish with the car.

We don't want to do this again in 1-2 months, and I'm not stuck on the whole vitara thing. I had my fun with them, and they are still by far the way to go for anybody wanting a 300-500whp range street/strip car.

I just want to go 9's reliably with a street legal/streetable D16 w/out wheelie bars. It's a great goal to work towards.

Up to ~500whp and 9000rpm is fine, but I think that 9500rpm and mid 500's-up is not reliable enough. I don't doubt that we could build another identical block and have it hold up fine, but the chances of failure are still to high for a reliable racecar.

SOHCinWA · 07-26-2009, 02:10 AM

I cant wait to see the new build. You guys did more than anyone thought possible.