Turbo Cams

James Thomas

James Thomas

"NO CLASS"
While on the other thread about rockers, it occured to me that my experience with roots supercharged 4.3's as far as cam profiles may be way off for turbo applications. I have seen several posts regarding Comp "412 & 415" cams. Does anyone have any experience with or thoughts on the "422" grind for our turbo engines http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=09-422-8 ?
This is a mild cam we use in some of our mid level blower engines with 1.5 rockers.

If that profile is acceptable for turbo applications then I will share a custom grind that is a little more radical. Aw... what the hell, it's a .502 INT. .510 EXH Lift / .224 INT. .230 EXH. DUR. @ .050 on a 114 Center Line. Do either look good for 18-22 p.s.i. for use on a turbo?
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James Thomas
 
sytyguy

sytyguy

Moderated User
James Thomas

James Thomas

"NO CLASS"
Re: Turbo Cams

Thanks Michael :tup: , I saw most of the posts but as luck would have it I missed the one that actually had the good info on the 422 grind. Oh dopy me! What do ya' think about the other custom grind I listed..... too much for a turbo application?
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James Thomas
 
sytyguy

sytyguy

Moderated User
Re: Turbo Cams

James Thomas said:
Thanks Michael
Ok.gif
, I saw most of the posts but as luck would have it I missed the one that actually had the good info on the 422 grind. Oh dopy me! What do ya' think about the other custom grind I listed..... too much for a turbo application?
Click to expand...

The other grind you listed would be a slight improvement over the 422, but I'd get with Waller (jwaller - www.wallerperformance.com) on a custom cam if you want something designed around a turbo combo. He's got some good grind specs on hand.

Hood
 
tytom

tytom

Donating Member
Re: Turbo Cams

Its a bit much duration on the exhaust side, imo,...although the 4series comp cams work ok, they are not "ideal" (whatever that is) for a turbo engine...at least traditionally turbo cams used to have a reverse split duration, with less duration on the exhaust side that the intake side. Lately, this is not so clear cut...depends on the rest of the combo, exhaust restriction (manifold vs. tube header) etc...so there are trends to go with a single pattern cam, that would be the same duration on both sides, but not necesseraly the same lobe though... So it will probably depend who You ask...
 
nightdiver

nightdiver

Active member
Re: Turbo Cams

tytom said:
Its a bit much duration on the exhaust side, imo,...although the 4series comp cams work ok, they are not "ideal" (whatever that is) for a turbo engine...at least traditionally turbo cams used to have a reverse split duration, with less duration on the exhaust side that the intake side. Lately, this is not so clear cut...depends on the rest of the combo, exhaust restriction (manifold vs. tube header) etc...so there are trends to go with a single pattern cam, that would be the same duration on both sides, but not necesseraly the same lobe though... So it will probably depend who You ask...
Click to expand...

What he said !

Ill replace the 422 with a custom one 276/276 that is a bit more agressive @ the intake @.50 . Still a hydro
Got to find some time first. :roll:
 
Windedv6

Windedv6

Ty n 10s
Re: Turbo Cams

I had a custom cam grind that uses the reverse pattern theory for my setup. Her is how it compares to the Comp 422:



............................Custom Grind .................Comp 422

Duration intake.............218...............................215
Duration exhaust..........214...............................220

Lift intake with 1.6........542..............................533
Lift exhaust with 1.6.....531..............................544

LSA................................114*.............................114*

Note: take about 33 points of of each lift number for 1.5 rockers.


My heads are vortec's that flow 270/203cfm and the cam is setup for 5,800 to 6,000 rpm shift points. To be honest about it all, the cam performed better when I switched back to 1.5 rockers. The 1.6 rockers were hurting my 1/8 mile times as I didn't spool as quickly. I am running headers and a .85AR exhuaust. I gain 2 tenths by keeping the exhaust open vs. closed, so the housing is not undersized. I am very happy with the how it is all working.

The theory of it all was explained to me just as Tytom explain to in his post. A reversed pattern may not be for every build but I am sold on it for mine.

John
 
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nightdiver

nightdiver

Active member
Re: Turbo Cams

It depens on the build. Most important is the static compression and exhaust vs intake flow. I will go to the dyno and see what happens with both cams. The guy that has the dyno has a tt porsche and a nice store just five minutes from, my house. It would be really interesting to see the difference between these two cams at the same engine.
 
chelo

chelo

filthy sy
Re: Turbo Cams

That cam profile seems to resemble my crower cam. I gotta dig up the cam card. I also run the 1.5 rockers and no problem.
 
James Thomas

James Thomas

"NO CLASS"
Re: Turbo Cams

nightdiver said:
It depens on the build. Most important is the static compression and exhaust vs intake flow. I will go to the dyno and see what happens with both cams. The guy that has the dyno has a tt porsche and a nice store just five minutes from, my house. It would be really interesting to see the difference between these two cams at the same engine.
Click to expand...

Well now I am interested to see also! As a genearls rule for blowers you need more exhaust than intake as the blower fills the cylinders under pressure but the exhaust needs more help to evacuate the cylinders. Of course this is a blower app. with a totaly different ex. set up.

Nightdriver let me know if you can do a comparison of the two cams? I would like to know if there is a difference and how much!
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James Thomas
 
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