toofast Posted May 31, 2008 Report Share Posted May 31, 2008 I just installed a marnel head on my car and was wondering which cam to go with.I was thinking about the schneider cam since i have the heavy duty springs.Plus what kind of performance gains will it increase?thanks Gary Link to comment Share on other sites More sharing options...
Technology Posted May 31, 2008 Report Share Posted May 31, 2008 What turbo do you have? Link to comment Share on other sites More sharing options...
toofast Posted May 31, 2008 Author Report Share Posted May 31, 2008 stock 12a Link to comment Share on other sites More sharing options...
Fanta Posted May 31, 2008 Report Share Posted May 31, 2008 you won't find that much with the stock turbo to be honest. It just isn't capable of taking advantage of what the cams have to offer really. Link to comment Share on other sites More sharing options...
Shelby Posted May 31, 2008 Report Share Posted May 31, 2008 if your looking at the 284 hyd cam you won't exactly be singing about it's performance with a stock car,, it'l move your power band up the rpm range a good amount an you'l deff notice a drop in low end power ,it's full power just gets start'd as your 12a runs out of steam but if you were to go to 3:90 rear gears and a larger turbo things are quite diff another thing with a mits turbo houseing your gona need to port the exh houseing to see all the gain from a larger turbo and this goes for any mits houseing , even the 12a can gain from the porting on the upper end , keep in mind all mits houseing are the same,, so geting a larger compressor wheel only makes the upper power range that much more restrictive and noticeable it simply a matter of gas volume flow out the waste gate and the poor flow design on the houseing Link to comment Share on other sites More sharing options...
toofast Posted May 31, 2008 Author Report Share Posted May 31, 2008 Thanks shelby for explaining why it wouldnt really do that much Ill have to upgrade a few other things before I choose a cam.thanks Gary Link to comment Share on other sites More sharing options...
Technology Posted May 31, 2008 Report Share Posted May 31, 2008 Yep, this is another epic thread, worthy of being in the FAQ. Shelby nailed it RIGHT on the head. toofast - good luck with modifying your car, and I am very happy you asked this question before making a purchase. Link to comment Share on other sites More sharing options...
toofast Posted May 31, 2008 Author Report Share Posted May 31, 2008 thanks technology Link to comment Share on other sites More sharing options...
Shelby Posted June 1, 2008 Report Share Posted June 1, 2008 hold on i didn't say it wouldn't do that much but was only trying to explain what else is need'd to get the full gain from a biger cam... you know how long it takes to port the exh houseing ,, with an air tool 3-4 hours at most ,if you have a good set of bits ,, with a mits turbo exh houseing probly the best spent 3-4 hours you'l ever invest in diff gear swaps is it right for every one, not at all but for that serious street fighter it may make all the differance in the world , on average it'l raise your cruise rpms by arround 500 but if you serious about puting tourqe on the road they are hard to beat , you can compair the rolling diff to about like going wot in 5th gear to wot in 4th gear from 50 mph,,theres a big diff now if you do a lot of interstate driveing and cruise @75 or 80 then 3:90s are not for you Link to comment Share on other sites More sharing options...
toofast Posted June 2, 2008 Author Report Share Posted June 2, 2008 Thanks shelby Link to comment Share on other sites More sharing options...
PDX87Starion Posted June 2, 2008 Report Share Posted June 2, 2008 Untill I see a dyno comparison where the "performance" cam makes more than the stock cam, I'll recommend keeping stocker. Well, with Chip the 292 schneider made about 30hp more @ 20psi. But all the other dyno comparisons the stock cam made more hp and torque. The others were roller cams now that I think about it. Perhaps its the roller rockers geometry that is the problem. Anyway more dyno testing needs to be done. Too many people assume that they need a big "race" cam for their street car, like the stock cam is holding them back. But the dyno testing that has been done shows otherwise. Link to comment Share on other sites More sharing options...
toofast Posted June 2, 2008 Author Report Share Posted June 2, 2008 I wanted to upgrade cams because thats the only thing that I didnt change- clevite rod and main bearings molly rings bored fourty over-new marnal head so thats why I figured Id post it to really see the differance between stock and a performance cam ,but I Know i should upgrade my exhaust to get the biggest gain for the bucks .thanks Gary Link to comment Share on other sites More sharing options...
Lidoidol Posted June 9, 2008 Report Share Posted June 9, 2008 Untill I see a dyno comparison where the "performance" cam makes more than the stock cam, I'll recommend keeping stocker. Well, with Chip the 292 schneider made about 30hp more @ 20psi. But all the other dyno comparisons the stock cam made more hp and torque. The others were roller cams now that I think about it. Perhaps its the roller rockers geometry that is the problem. Anyway more dyno testing needs to be done. Too many people assume that they need a big "race" cam for their street car, like the stock cam is holding them back. But the dyno testing that has been done shows otherwise. Heron, denny, and myself have all seen firsthand the problems with the roller rocker conversion, HOWEVER... The M6 head comes with stock roller rockers... correct ratio... designed for the head. WILL NOT crush the valve seals... with the right lift... easy way to fix any concerns: Ferrea valvetrain in the works Another issue to be addresse is the cam profiles available, TIM_C hit it on the nose if anyone can find that post. The Schneider cams, although high quality, were originally designed for a NA motor. Turbo motors need a specific grind. same as nitrous and superchargers. Same reason I dont understand why guys have destroked the g54??? "It needs to rev to make power"...??? Shelby, back me up here, when was the last time you saw a street stock Big Block Chevy go over 7000RPM??? Point made Link to comment Share on other sites More sharing options...
Technology Posted June 9, 2008 Report Share Posted June 9, 2008 I compared a stock cam to a 274 with the same setup and the stock turbo, I gained close to 10 horsepower. Lost 30 lbs of torque, but I gained that horsepower! Link to comment Share on other sites More sharing options...
PDX87Starion Posted June 11, 2008 Report Share Posted June 11, 2008 (edited) I compared a stock cam to a 274 with the same setup and the stock turbo, I gained close to 10 horsepower. Lost 30 lbs of torque, but I gained that horsepower! Wow thats a big trade off. Interesting that you lost so much torque and still gained HP, considering you need that torque to make HP (Torque x RPM / 5250= HP). You must have been able to rev a lot higher with the 274. For a race car I guess that 10 hp would be beneficial if its where you can keep the RPMs at. But for the street, give me the 30ftlbs of torque. I'm still concerned why we loose so much torque with a performance cam. Shouldnt the torque stay about the same but just be moved up the RPM band resulting in more HP. Like just retarding the stock cam a couple deg's...the torque would be moved up the rpm band resulting in greater HP, and the loss in torque should be very little. Seems to me like torque is a result of how much air and fuel is being exploded and if the cam profile is superior, it would get that air and fuel in and out more efficiently even at mid RPM's which should not kill the torque. It just proves to me (in my mind) the the stock cam is not a "problem" that needs to be fixed for mid to high (but not super high, or race) performance levels. Edited June 11, 2008 by PDX87Starion Link to comment Share on other sites More sharing options...
Dcrasta Posted June 11, 2008 Report Share Posted June 11, 2008 EIP ran 10 second quarters with the Stock cam.. Its not as bad as people make it out to be.. Link to comment Share on other sites More sharing options...
Technology Posted June 11, 2008 Report Share Posted June 11, 2008 Well, I lost the huge peak at 2500-2600 rpm, but the rest of the graph was above the old curve, so it should have felt like an improvement, but it didn't kick my butt as much as before. I think what I'll do is modify my stock cam exactly how I did my 274, and after I get it tuned, I'll do a back to back comparison, with a little tuning. If the stocker isn't much worse than the 274, I will ditch it or try a 292 (which I really want to try anyway). Link to comment Share on other sites More sharing options...
PDX87Starion Posted June 17, 2008 Report Share Posted June 17, 2008 Heron, denny, and myself have all seen firsthand the problems with the roller rocker conversion, HOWEVER... The M6 head comes with stock roller rockers... correct ratio... designed for the head. WILL NOT crush the valve seals... with the right lift... easy way to fix any concerns: The duration is reduced (late opening/early closing I think) with the roller on a stock cam, if the M6 comes with rollers I would really like to see what the physical cam profile looks like and the specs. I'm guessing it should resemble a typical roller cam with a large flatter point to it. Link to comment Share on other sites More sharing options...
Shelby Posted June 19, 2008 Report Share Posted June 19, 2008 has any one in the US ever dyno'd the M6 roller cam , i'd love to see how it compairs to our stock cam more important i'd love to see the cam profile and compair that to a stock sliper cam Link to comment Share on other sites More sharing options...
BrokenquestTSI Posted July 18, 2008 Report Share Posted July 18, 2008 i think the torque loss would take some fun out of the car. (on the street) Link to comment Share on other sites More sharing options...
Recommended Posts