Originally Posted by V8_DSM_V8again

Also ask jose about the 230/230 custom comp they had made..

Originally Posted by Rpm2800

Im no expert , but the problem with people talking about turbo cams is that that the exhaust runs through the turbo . That causes back pressure issues to come into play. With a belt driven supercharger you usually have a larger ex durtation. It's basically seems that it's more simple than a turbo cam and more matter of how much split and lsa, although valve events come into play with any setup whether it be turbo , NA , nitours or supercharger. Belt driven superchargers cams usually have more off a general agreement as being exhaust biased. It's usally how much of a split... will it be 220 in 224 ex or 220in 230ex. Still, though valve events, Rpm , head flow, etc matter but........... it's usually agreed that more exhaust is needed. Although I I don't know if you can pick the best cam for any combo without knowing the combo and what the owner wants.


Turbo engines have to deal with the above events, PLUS more things mainly involving exhaust issues. With a turbo , there is no magic turbo cam for every application. On some setups, a sinle patter may work better , some an intake bias , and some an exhaust bias. I think it's also about valve timing (valve timing events), and not just intake and ex , because like somebody said , there is cases where you can have a cam with larger exhaust that has less overlap that a single pattern or larger intake cam.

If you have an effiecient turbo exhaust housing , header design and , exhaust flow on heads, it will need a different cam than a setup with a log manifold , low flowing ex port, and a small or non effieceint ex housing.

When you see people that say a turbo needs a certain cam without knowing the setup , usally they probably don't know much about turbo cams (NOT that I do) . People that say "a turbo cam always needs a single pattern cam or larger intake", or even certain lsa and don't know the engine and turbo system setup are usally just reapeating what they hear, since that is what most off us see. (Cams like 224 in 224 ex ... or 230in 224ex and usually with lsa in the 113 to 116 range.)

People that just say " a turbo cam has a lager exhaust" are usally thinking that a turbo cam is the same as a supercharger cam. The engine and turbo system seem to matter. I have heard people that know a bit say, that the more effiecinet a turbo system is , the closer to a NA type cam you can use. ie : single pattern or bigger exhaust. Some of the 6, 7 , and maybe 8 second turbo race cars you see have bigger exhaust , but they have huge exhaust housings with not as much back pressure , as well as very efficient headers, and probably good heads.

I think Jose says that if you have an effiecient turbo setupe where the back pressure is less, you can use a single pattern , and if you have a less effiecient or log type setup a reverse split is better . People say it's because of backpressure , reversion , and keeping the intake charger from getting contaminated. But Notice he considers the setup and does not just say reverse, single exhaust bias. Also, turbo cams are probably one of the most controversial and highly dissagreed upon things in motorsports it seems. Often times professionals don't seem to agree. That's not to say that a certain cam will or will not work or a given, motor. It just may not be optimum. You have to also consider .... are you looking for more power, faster spool, bleeding of tourque, more power on pump gas etc. People also have their own ways of thinking . But again i think it's important to consider the setup.

Originally Posted by Rpm2800

Is this something we would have to call him about . If not Paging Jose,............................................. .................................................. ................. Come in Jose.

Originally Posted by Race-Prep

Hello all, I actually specced this cam for nitrous before I got the turbo installed on my car and yes, it is an STS system but with the GT76/.80AR turbo. The cam spooled the turbo to full boost (only 6 psi for now) by 3000 RPM on a stock engine with this cam 224/232@.050" with .600/.600 lift on a 114 LSA. The car put down 454WHP and 420ish torque. I was very pleased with the performance of the car as the engine is totally stock save for a pulley. All this is through a Moser 12 bolt with 4.11 gears so it did real well considering. I think what is going on here is the fact that modern turbos are so well designed compared to a few years ago that there is very little exhaust restriction comparetively speaking. The goal with this cam was originally to get the largest grind possible to pass emissions in CA so I specd. it with REALLY fast ramps, in fact they are a Ford 5.0L racing lobe from Comp....(hey it was the quickest ramp I could get). But I think because the ramps are so quick there is actually VERY little overlap in the low lift ranges and therefore allow longer exhaust duration to work well without promoting reversion. We will find out if it works good on a bigger engine with more than 18psi very soon as the new engine is almost done and I will be letting you all know how it goes!

-Bryan

Originally Posted by JZ 97 SS 1500

No need for a big cam guys. They sound good but don't make a huge difference in power unless you simply have to rev the engine extremely high.


Bryan, one question, if the turbo spooled by 3000 rpms, why is the torque so low?? The torque being lower then your HP is indicative of a slow spooling setup due to a big turbo. Unless your torque is dropping off after the intial spool up.

Originally Posted by Full Throttle

A stock cam for a grand national is 107 l/s tight lobe center works better with turbos on small duration cams. Remember we are looking at overlap and a cam that is say 204 @ .050 on a 108 might have less overlap than a 230 duration cam on a 114. Look at event timing and make sure the exhaust does not open too early. The Z06 cam needs to be wide because of the big split. That big turbine wheel in the 88 will also like about 4 extra degres on the exhaust side I would suggest a 224/228 112 is the tighest I would go with that duration. 114 is the most. Using an X-ER lobe on the intake to open the valve fast and a regular lobe on the exhaust to open it slow works good too. Getting the intake open as fast you can is a benifit but we don't want to open the exhaust as fast. PM or e-mail me some head numbers and rocker ratio and I will be happy to work up my opinion and give you the lobe numbers to work with.
Mike

Originally Posted by MIGHTYMOUSE

anybody got graphs and stuff of the lingenfelter or the same type cams?

ed, what do you know about the cam in the kordis vette?