I know cam's have been discussed to death, but..

[Boehlke]

Hi all! I've been searching for info on the Thrasher cam, 222/222, and I haven't been able to find much info. The basic story behind my engine, is I shattered the #6 cylinder, so I'm building the motor w/ forged pistons/rods + other misc. goodies. I need a very agressive cam, and I'd rather not wait for a custom grind(although it is possible). Anyone have any experience with a cam like that? Any opinions/recomendations? I know it will move my max power up in the powerband, which isn't an issue since the valvetrain is being replaced(including the timing chain) and the pcm is being re-written. The car is set up for drag racing, and nitrous is also run. The car is also an M5. From what I've seen it should work well on n/a aplication since I'm not too worried about drivablity. Any opinions/insight is greatly appreciated!

[Dominic]

The thrasher cam may or may not suit your application - your best bet however is to go with a compcams grind of your choice... even if its still 220+ duration it'll have more lift throughout the lobe for maximum power. What all is done to your engine and what rev range are you going to be racing in?

[Boehlke]

Thanks for the reply Dominic. I know rockers wouldn't be the best way to handle it, but couldn't I use a higher ratio rocker if I wanted more lift and the same duration? Or would the cam offer better control on lift?

As far as the engine goes, this is what I have: the heads and intake manifolds are polished, extrude honed and port matched, throttle body is ported and polished, intense springs, titanium retainers, intense pushrods, stock rockers, radiused valve job, approx 10:1 compression(pistons/rods are custom so I'm not sure on the final ratio as of now), roller timing chain, RK Sport headers, no cat, slp loudmouth exhaust, MSD DIS-4 ignition, slp CAI, whisper lid, taylor wires, ngk tr6's, 42.5 lb injectors

Like I said before, the computer is being re-written. I have no idea where the thrasher cam would make max power, so I don't know how high I'm going to shift. I planned on raising the rev limiter and having it dyno'd to determine max power, and then shift accordingly. How high can our engines rev before flying apart? Has anyone ever calculated that out? I don't have too much of a problem raising the limiter, but I'd get a little worried around 7k, if it went that far. How high are the GTP guy's revving with built valve-trains?

[Zooomer]

Dan Taylor of WI ran the Thrasher cam in his GP GT. Someone posted dyno #'s a couple months ago on this site. He ran 15.4 before the cam, then 15.4 after the cam. He then went with a high stall converter and that dropped him into the high 14's. After that a vavle dropped into a cyl and fuxored the engine. I would recommend against that cam for the L36.

[Magnus]

The thrasher cam is definately not an ideal NA cam.

[Boehlke]

Ah, thats interesting. Is it just too extreme or what? What are the differences in the L67 and the L36 that enable the L67 to better handle that cam, besides the power adder? I want the cam to work well with nitrous too, so it's not going to be just for n/a. Is the powerband moved too high or what?

[Dominic]

For the limited amount of air the 3.8L can manually injest the thrasher cam is incorrect for it... i.e. too big... which can be worse than too small.

With your setup you can make a lot of power with the right cam, but really you need to do the research and spec out your own one if you want to be fully satisfied. I've done a lot of work on my own studying how each value affects the engine performance and how it relates to different RPMs, displacements, induction and exhaust setups, and the like. In doing a lot of research I found many flaws in current cams being offered by companies, and I dont know why they exist.

A piece of advice I can give you though is if you're looking at two different cams and one is milder than the other but not by much, you're probably better off going milder.

The cam lift should be determined by a flowbench of your heads; the cam duration by the CR, rev range and powerband desired. Most people agree the stock heads are good to 0.500" lift. I would try to keep the duration between 206 and 218 for intake and exhaust... you're modded nicely, but its still only 1 US Gallon of displacement [img]smile.gif[/img]

I dont recommend going past 6500RPM unless you're positive you can do it, and only that on a nice stif valve train. The stock valve train will float over 6250...

I know thats a lot of information thrown out there in an unorganized fashion but hopefully it will help :D

[Boehlke]

Thanks, that helps alot. I remember you saying in another post(I think it was you) that when given a radical cam and a cam that makes slightly less hp it's better to go safe. The information you posted makes a lot of sence actually, and that was what I was looking for. Thanks again.

[Blue Flame V6]

hey boelke where are you @ in Kansas?

[Boehlke]

Right outside Kansas City in Overland Park. Why?