Driving Impressions (Y-TRY Camaro)

[Y-TRY]

Well, I had my first full Saturday night out in the car this weekend. I'd call it more of an "extended test drive".

The car was a blast. The TKO's overdrive made easy work of cruising down the freeway. The power was crazy-fast, and the poor Z-rated rubber didnt have a chance against my right foot. I made a couple notes, though:

1) The 3.89's were a carry-over from my old combo (275/60/15's,4-speed, peaky 355). Even though highway cruising wasn't an isue, the steep 1st gear (3.27) and short tires had me shifting into 2nd halfway through the intersection when I was leaving a light. On hard acceleration it was non-existant. I've decided from this drive that I don't really need the gear that I did with the 355. I'll be swapping in some 3.25's very soon. I'll enjoy the broad power curve alot more this way. This engine wants to really stretch out more without having to shift and slow the turbos down so often.

2) With the stiff suspension the stock style seats are feeling a bit dated and rough. More modern seating is needed to keep the ride a bit more comfortable. These look great but don't have the padding and support of a Corbeau or Sparco. Along with the gears, this will be the next order of business.

3) The carb tuning isn't all that bad. My main issue is getting the boost under control. For some reason, the Wategates don't open when I want. Once I get the boost where it should be, the carb tuning will fall into place. As we saw on the dyno, it runs super rich at low boost and leans out when it goes over the 12psi the carb is jetted for. I ended up giving it more timing (24 degrees total) and the car seemed to like it better than the 20-degrees I had. It was passing alot of raw fuel into the exhaust and it would continue to pop for a second after the car was shut down, like popcorn.

4) I was hoping the turbos would quiet the exhaust a little more than it does. As it is now, the exhaust runs out of the downpipe and out the back of the car with no mufflers. Just turbo-to-rear bumper, 3". It's pretty freaking loud still. So I'm going for some 18" bullet-style mufflers to help my ears. I don't want a chambered-design, and the packaging under the car limits me to that style.

5) Low stance + CalTracs + Speed bumps = Crunch


Of course, I have my share of bugs to work through. Finding the right boost and timing will be some trial/error. But even untuned as it is and only 6psi it's putting well over 700hp to the ground. I can't wait to see what it does at >12psi and the carb jiving.

I also have some turbo questions that I'll move to another forum. I just thought I'd share some results with you guys. Maybe someone is considering the same issues with their car and could glean some advice from this.

[XcYZ]

That's an excellent report. I have to agree 100% on the 3.27 first gear in the TKO - it's just way too deep and then it spreads out the gear splits of 2nd, 3rd and 4th too much IMO. Good tranny otherwise, I never had an issue with it and it shifted great.

What are you using for tuning? Do you have a hand held wideband O2 meter?

[Y-TRY]

Originally Posted by XcYZ

That's an excellent report. I have to agree 100% on the 3.27 first gear in the TKO - it's just way too deep and then it spreads out the gear splits of 2nd, 3rd and 4th too much IMO. Good tranny otherwise, I never had an issue with it and it shifted great.

What are you using for tuning? Do you have a hand held wideband O2 meter?

Thanks, I try to report stuff that can help others out.

The gears, seats and mufflers are the first things I'm adjusting after driving it. Things that look good on paper sometimes don't work well in the real world. I think the 3.25's will be good, and I'm even considering Richmond's new 3.15's just to be different. It's a good in-between 3.08's and 3.25's. The TKO has kinda resisted 2nd-3rd shifts with any gusto, but it's probably me.

The specific tuning I've done so far is on the chassis dyno and the sensors it has. Nothing hand-held, although that sure would be nice. But the car needs a load to boost up, and the dyno is better than trying to do it and drive, even with a passenger. On the road, boost is coupled with tunnel-vision and it's hard to even look down at the gauge.

[Blown353]

I would think the 3.08-3.25 rear ratio would be great with the TKO. I run 3.42's myself with my TKO and first is still a bit steeper than I would like. I have no issues launching the car, which is 3620# without driver. A bit taller gear in the rear would make things more practical; right now I RPM-out of 1st at about 45 mph, and 1st gear is of course totally useless as far as being able to use any amount of power. Well, 2nd gear is too, so maybe the taller gears wouldn't help in that department. It would at least let you "roll out" from a standing start a little further before going for 2nd gear.

I also like taller rear end gears to keep driveline speeds sane, which cuts down on vibrations and also makes u-joints live longer.

The other option is to sell your TKO and go for a TKO-600 with the 2.89:1 first gear, although I still think the 3.89's would be a bit too low for that; 3.23-3.42 would probably be more ideal.

Troy

[Vince@Meanstreets]

. Sounds like a fun ride. You guys running TKO's hows your top gears? I was going to set up for 3.73's but now may go 3.31's or 3.55's. Any input on this? Again congrates , remember rubber side down please!

[61Bubbletop]

Cool write up!...Thanks!

[Y-TRY]

Originally Posted by Vince@MSperfab

. Sounds like a fun ride. You guys running TKO's hows your top gears? I was going to set up for 3.73's but now may go 3.31's or 3.55's. Any input on this? Again congrates , remember rubber side down please!

I like the TKO. For Overdrive transmissions its pretty much one of the toughest rated out there and, when I chose it, one of the easiest swaps.

When I was deciding to leave my 3.89's in or not, originally, the only math I really did was to see how it'd be on the highway. So I decided to leave them in. I could see there'd be a big drop from 1st (3.27) to 2nd (1.98) and I blew it off thinking "well, I guess it'll spool real good in first". But, as I mentioned, after driving it I think it's a better trans for something REAL low like 3.08's even. With this trans and engine combo I've pretty much had to throw-out whatever I thought about gearing. Old-school thinking was to ideally gear the pee out of it with tall tires and then rely on OD to cruise. But that was with peaky, big-cammed, high-compression small-inch engines. Doing the math now, I see that the combination of 3.27 1st gear and shorter tires with the 3.89's were the equivalent of putting like 6.14's in if I'd left the 4-speed and 275/60's on the car (speaking final drive ratio). That suddenly doesnt look so cool.

I'm going to those 3.15's like I said. This engine doesn't need to spin that high to be fun and it'll only make highway driving that much better. I don't have a complaint about the higher gear ratios, especially if I let them spread in the rpm range by changing the rear. My only complaint is 2-3 shift at high rpm. I've kinda had to ask nicely instead of slam it like I'd like. Nothing like the Muncies. Maybe Tremec is trying to disclipine me some. I even think 2.73's would be fun but I don't want to be shifting into 4th at 170mph. That's just too fast for my own good.

To answer your question: Unless you're building an engine like I described above, go for the lower gear (numerically, taller, you know what I mean) with this trans, IMHO.

[hotwheels]

awesome write up man............700hp with only 6psi





hotwheels of turborides