You can run an AP2 motor to an AP1 trans. That bolts up just fine. You just have to also use an AP1 diff if you do since those bolts would be different (8mm vs 10mm). Personally I'm planning on doing AP2 motor, trans and diff housing and as suggested compensating for loss of gearing by running a tall tire like a 315 in the rear.

 

You have to change out the flange that connects to the drive shaft as Jason described earlier in the BSP thead. The diff and driveshaft doesnt matter. This is very simple to do. Since the tranny is considered one unit, swapping parts of it with the ap1 & ap2 is illegal from my understanding of the rules.

 

Just read a post that CKIT posted saying he broke 2 diffs and 6 hubs running on BSP sized wheels/tires. Is this really going to be that big of a issue running in BSP? What can we do to strenthen the rear end up to prevent this failure? (atleast as often) Granted CKIT is also making almost 500whp but I'd almost say the added power would be easier on the rear end because it would spin the tires easier, at BSP power the tires might not spin as easily and in return stuff may break. I've already got my speadsheet going and I'm directing money towards my other banks savings when I have the free money and tempted to slurge. I'm planning on saving up enough to cover the build and then when the time come I can fold or go all in. Normally I would buy parts here and there like I did with the STR build but we have to many unknowns to commit and buy parts for a class I might not move to. I love STR but I have a urge to go faster and honestly to win STR nationally I feel like I'm at a disadvantage with my ap1. Since they didn't total my ap1 and its getting fixed It would cost more money to buy the STR car I want then it would to just go BSP.

Hopefully Marc P paves a yellow brick road for me to follow!

Marc- Sorry to beat a dead horse but from my understanding both transmissions will bolt to both blocks just fine. The legal issue come in play on the other side of the transmission. The trans output yoke and diff input yoke are different between the ap1 and ap2. I think the ap2 uses bigger bolts. So to legally run a ap1 trans to a ap2 motor you inreturn have to run a ap1 prop shaft and diff. Or as for someone like me that already has a ap1 trans and diff I just need to mount the 2.2 motor to the stock trans. This can also be done by using the ap1 motor connected to the ap2 trans/prop shaft/diff. The only legal issue I see is if you tried to keep the ap2 diff and run a ap1 trans, they wouldn't mate up without changing the output on the trans or a custom prop shaft. *disclaimer I could be all wrong but thats what I thought I found when researching this issue)

The bigger question is which is better gearing to have? Top speed of 67ish or 71ish? (not exact on the top speeds I neeed to do the math but have a quiz to take in 1.75HRs and don't have time)

Also whats the best wheel tire combo 17-18x10.5 with 285F/295R or 17-18x11 with 285-315F/315R? I feel the bigger tire may have overall higher G holding ability but may be hurt in acceloration and break things more often. Plus the whole fitment issue but we can work around that pretty easily if you don't care about your fenders. Can we get some info from the guy that won this year? That would be a huge help since hes way ahead on development. It would save from making wrong purchases and having to buy anything twice.


-Just a guy that loves to tinker/wrench

 

you can't do anything to strengthen the rear end, except run an AP2 diff. The weak part isn't the diff itself, but the carrier caps. A few companies offer alternatives, but they are not SP legal.

 

Jason doesn't post much, but his username is spaf. I am sure he would answer a PM or two.

 

BTW I asked Jason his power figures and he did say that he was in 280whp range. However that was on church's dynapack which would be equivalent to about 220-230 on a dynojet. Which is what we made before in str without some bsp mods. He also complained about heats oak with the itbs

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Thanks for that info, the guy I spoke with at the last tour acted like the car made amazing power. 230 is nice but not much above STR prep. Question is how much midrange TQ and HP the car makes.

Heat soak, hmm.

 

280 at church is probably in the 240-245 range. I've seen a few comparo's with a local dynojet on the Z forum. For reference a healthy 03-06 Z in full BSP trim makes in the 275-290whp range on a dynojet. An 07+ will make upwards of 315whp on E85 IMO. Tq is about the same b/w the 03-06 and 07+'s however, and the 03-04's make it earlier in the power-band. Z's are heavy, though .

 

Same dyno, same day, same tire pressures, same diameter, fluids, temps, etc ... and even then it may vary. I made 189-207 on our local dynamics roller depending on the day. I even got caught up in numbers thinking something was wrong with my car. I had it compression/leakdown checked to verify only to find out the problem was tuning, but once fixed, peak numbers didnt change. Dynos are great for tuning, but not so much for comparison. Check out the club racing results where dyno pulls are mandated, it can vary pretty significantly. As a result, i don't put much value on dyno results. I just make sure I'm in the ballpark and the compression/leakdown #s are good.

-Marc

 

My current plan is to run the AP1 F20C with the AP2 tranny, driveshaft and diff housing. The only thing that might change this is if I can find a reliable source for a used f22. An engine swap is easy enough to do and with the Northeast big events starting as early as April, I'd rather focus my attention on getting the car set up for the additional grip the Hoosiers will provide. And who knows, maybe the lack of torque will mean I'm the only BSP car without a blown diff at the prosolo