Javier97Z28

Hey guys please help me out with this.. I asked once before and got very mixed opinions on the subject.

I picked up the 224/230 XE grind as a complete kit from Combo Motorsports including springs and 1.6 Pro Mag rockers.. I have a GM Extreme Duty LT4 set as well.... so I'm set as far as proper drivetrain is concerned.

What should I have my PCM set to shift this cam at?

The tranny is holding up well, 2800 stall (for now), and a Transgo shift kit stage 2....

Aside from that, heads are stock, and I have LT headers..

Seth over at Combo recommended I spin it to 6500, which is a little past peak he said. Any ideas? I thought 6500 sounds a little high...

Thanks! Please help me quick as Bryan at Pcmforless has my PCM right now, and I'm going to be setting this up this weekend (install party woohoo!)

Mindgame

You really need a dyno graph to make good calcs but this will help:
http://www.bgsoflex.com/shifter.html

General rule is to shift 10% past peak hp (6k shift at 6600 etc) but it depends on the tranny gearing and other things.

-Mindgame

96z

I went through this last fall with my A4 combo....the Tranny doesnt shift at the exact rpm set in the program. There is a slight delay 200-300 RPMs or so. The 3-4 shift for some reason takes a little longer 300-400 RPM's or so.

I was told by a couple board members to have the tranny shift 200 RPMs past peak power. So for example if you want the tranny to shift at 6500 RPMs set the shift RPM to 6250, etc. You have to experiment. My advice would be for the WOT table set the mph lower than expected so that the tranny will shift once the RPM is met. To shift at WOT both the designated MPH and RPM need to be met....

dust6928

you should shift about 200rpm's past your peak hp. i am going to go with the cc503 and they (comp) told me it would be done by about 6000rpm which would make the shift point about 6200. i plugged everything in on desktop dyno and it said peak hp was at around 6100 so you should be safe at around 6300rpm shifts.
And that is correct about the tranny being slow about shifting if it is stock. With a little work it will shift about as fast as you can shift it.

Javier97Z28

What would be considered "a little work" then.. shift kit like I have?

I'm thinking about having Bryan set it to 6200.. sound OK guys? or am I going to lose any ET/MPH?

I know it's best to determine this on a dyno.. but unfortunately NOONE around me has OBD2 LT1 Edit.. nor does anyone want to buy it w/ me on a multicar package sooo I have to rely on sending my PCM back and forth

dust6928

shift kit helps i am sure but i honestly dont have a lot of experience with od trans. i believe, if you havent already done it, you put a stiffer spring in the servo to get quicker firmer shifts. you have a great stall but damn thats a big exhaust. that thing outta be able to support a 1000hp motor. anyways, if you shift it yourself i would have it set to about 6200 which means it should hit between 6300-6450 and you wont be able to be late with it. if you let it shift itself then maybe 6300. another delay in shifting is you, most people set their shift lite about 200rpm's lower so by the time they react it is about where they need to be.

Javier97Z28

Yep.. the separator plates are bored out, stiffer springs in the 1-2 accumulator and.. servo has upgraded springs.. the valve body is modified w/ new springs and valves.. everything is all set

So, I'll be letting the tranny shift itself, i'm lingering on 6200rpm shift point so that it will shift around 6300-6350...

CANTONRACER

You really need just to go to a dyno and get a printout of your power and then get the PCM calibrated.

Any other way is just simply quessing.

Let's assume your thinking your car is making peak power @6300 rpm and you set the shift MPH to basically shift when the car is around 6500 rpm, but your combo really makes peak power @ 5800 rpm. Don't forget about valve float either.

Your gonna lose an easy .2-.4 tenths and 1-2 MPH just from being in gear way to long. Your simply out of power but your car will still be in gear, just pulling slowly until you hit your preset shift points. You wont notice really that it is in gear to long in 1rst, but in 2nd, it will drag it out.

I would rather be a little low and go from there.

Mindgame

Someone gets it.

-Mindgame

Javier97Z28

Well wait.. it's not that I "don't get it"....

I'm looking for somone with a similar combo who has had good results with this cam.. and then I would like to know what they're shift points are, that's all.

I fully plan to dyno the car to get an idea of how it's running on Bryan's tune when he sends it back later b/c I'm looking to install gears in a few months anyways.

96z

I can let you know what my shift points were when I get home. I had a GTP 226/230 cam....

CANTONRACER

Is that a GTP 3?

Javier97Z28

cool thanks shoot me an e-mail or a PM

96z

No, I asked craig about it when I first got the cam and he said it was a custom grind...

unTAmedLS1

I have the same setup as you basically in a 97 Formula and I beat a stock 405 ZO6 shifting at 6400