Here is what the tech guy said was good. I talked to 2 of them. The part # is XT12-251-4-H Rpm range from 1 - 5000 rpms. Duration at .050 is 206 - 206 Lift is 432 - 426 and lobe sep is 110 I asked him about that lobe sep being 110 and I forgot what he said but he convinced me, so me being the easy sell I bought it. Summit didn't have it in stock and Comp Cams only had 2 so I got one of them. Any opinions? I hope I didn't screw up. I figured since it's out of stock at Summit and Comp only had 2 I better get one. Thanks. Brad...

talk about tame...jeesh

what did you tell him, you have a GN? LOL

the tight lobe sep is fine because of the low duration valve overlap @ .050 is

(206+206)/2-(110*2)

206-220= -14

so that's good, kinda a lot of negative overlap but still ok its just the low duration and lift is kinda bad

i would've just called up duttweiler and let him pick you out one. I got mine for like $160 shipped. Told him all my specs and he had one custom ground for me with the lobes he wanted to use.

That cam is going to make an assload of torque and with the quick spooln' T3s good luck with traction!

I know I advised you in another post to consider going with a milder turbo
friendly cam but that's quite a bit milder.
Basicly that is a hi energy cs 252H-10 206/206 .425/.425" 110
except with an extreme energy series intake lobe 206/.432"
Well its always better to be slightly under cammed than over cammed.
It will be much more responsive with your stock converter thats for sure.
The turbo will make the horsepower.
How is it to be installed? advanced, retarded or straightup?

The only issue now is your high mechanical compression ratio.
It's going to limit the amount of boost you'll be able to use on pump gas with out an intercooler.

Brad,

When i purchase my cam for my Z with the supercharger, I remember reading that the turbo, supercharged, nitrous applications like lobe centers around 112 deg LCA. I got my cam from delta custom ground very similar to the ZZ3 cam. If my memory serves me right it is @ .050 208/222 with 475/505 lift. I think the article was in Chevy Hi performance and it also said that for these applications, a cam with a bit more on the exhaust side really helps it flow.

Oh yea, New Years we are having a party and of course you are invited!

F-Bird'88, I know you did and I should have just told comp to make one like that but I asked what would they recomend and he asked me some questions about my motor and came up with this cam and it's too late to change cause they sent it out today.
I was thinking it was a bit mild myself but I don't know sh!t about cams. I could send it back and exchange it I'm sure. If one of you guys could tell me what would be the best cam cause I'd like to do this right the first time. My motor specs are this.

350 .060 over
Vortec heads and a Edelbrock Performer RPM intake and a Edelbrock 1412 800 CFM Carb, and hyper pistons. Compression is about 150 on the compression gauge maybe a bit less. As for rejetting the carb, I learned how to do that the other day but Summit doesn't have a kit that goes as high on the rods and jets like you recomended in an ealier post so it looks like I'm gonna have to buy them seperately. Thanks for the help.

I also got a pile of parts and gauges today. My house is a mess with the boxes and them damn styrofoam peanuts Summit loves to use. Well anyway I got my EGT meter and was wondering if I wrap the headers won't that raise the temps considerably? That Aircaraft EGT is nice. How well will my in dash fuel gauge work with a mech. pump. I have the gauge with the isolator. sure looks pretty and I can't mount it on the firewall cause of rules. That sucks and I have to keep the hose level with the gauge and iso. That's gonna be fun.



What would you reccomed? I'm a bit lost in this area.

Brad...

Yea, I have to agree with 89ProchargedROC, that does seem like a really mild cam..... I'd like to think that they have qualified techs to recommend camshafts, and not some monkeys picking random part numbers, but who really knows.. I hope it works out for you..

Myself, I'm going to leave that cam that's in my motor right now.. It's a Comp Camps NitrousXP cam.. 240/253 @ .050 and .507/.525 with 113 LSA..

In theory, the turbos should like the wide LSA and greater exh lift/dur...


Anyways, happy hooking Bhaas =)

Cheers!

what did you tell him, you have a GN? LOL

bhaas. just to give you an idea. my little 3.8l buick has a cam that's 210- 206 @.050 112 lobe. fresh stock motor. all i did was clean the bowls in the heads myself. with a 52mm turbo, 21deg total timing and 23lbs boost it made 507hp @5500 and 575ft lbs @4400. these are flywheel #'s. this is not a very aggressive tune-up either. as long as your carb moves enough fuel and you have a good flowing air hat you'll make plenty of power with that cam. do yourself a favor and get a big electric fuel pump. you will be wasting your time with a mech or holley blue type.

Those of you were are reccomending to him a wider LSA, you should go back and read my post

with the short duration, you need the tighter lobe sep for valve overlap. Otherwise if you widened it, you'd have waaay too much

bhass where did you get the AN style EGT gauge? I like em because with 4 of em you can monitor the whole engine.

B4C, I got it at an aircraft supplier place. Here is the link.

http://www.aircraftspruce.com/catalo.../micro1egt.php

thanks man :-)

Duration at .050 is 206 - 206

Thats torque for you. I assume you plan on driving it on the street? thats the perfect cam for it, and even MORE perfect for a stock converter. Hell, my 224/234 @ .050 114 LSA idles like stock in my 355, smooth at 500 RPMS in gear.

but like was said, better under cammed than over. under cammed? okay so we lose a little top end. over cammed? then you need new gearing new converter more fuel crappier idle etc...
thats how i see it right?

According to DD2k (not that anyone cares) you have nothing to lose by going with a bigger cam though. your VE% drops a smidget down low but you gain gain gain up top. but TOO much duration and low-rpm cylinder pressure drops and... goodbye drivability. heres a graph for ya...
it doesnt, of course, assume twin turbos. that means your torque curve will come in sooner than it appears, also i limited it to 15 PSI. thats probably more than you will run anyways, i would imagine, on hyperuetectic pistons... i wouldnt go more than 7-8 PSI without an intercooler anyways.. but thats my opinion.

and... Bhass are you still looking into EFI? It's worth the time and money to research i would think. are edelbrock carbs ideal for turbo applications? hmm...

oh yeah, and, NOTE the big lack of horsepower. not enough cam. the heads dont help either... although those are MILD vortech's... does anyone have any good flow charts of a vortech head? Just for fun i threw some AFR 220's on it and it didnt improve much at all... so the heads are not limiting power here.... the cam is... according to DD2K. i swapped around turbos and blowers too... not much to be gained there either. ill post some more.

here this is with JUST a cam swap. boost needs to breath, as this clearly demonstrates. same everything else....

the new cam is 224/234 @ .050 with a 114 LSA and 4* of advance ground in. Its the biggest you can go with the stock converter in my opinion. (i have the identical camshaft in my motor)

My goal is to run 10 second 1/4 miles. Will the cam I'm getting let me do that? I'd also like to do wheelstands. I want the most power I can get. If I need another stall converter then I'll get one. F&*% it. Money is no object anymore. I want power and speed. It seems every time I turn around I'm spending another $500 or more at Summit so why stop now. Thanks King for doing those DD's. Those are cool. Just a note to B4C and King, it's BHAAS. <-- Read 10,000,000 more times. That's 2 A's not Bh *** Everyone does that. With all the gauges and crap I have to install I've now come to realize I'm not gonna be able to keep my heater I'm gonna have to tear it all out. I don't have any more room to really drill holes for stuff anymore. So much for keeping the car the way it is. I really, really don't want to do that but I have no other choice at this stage of things. Looks like it's quickly becoming a race only car. One more question. Should I hook up water coolong to the turbos? Does it make much difference?

Brad...

Brad,


I bet we can work something out for the gauges with some Kydex plastic. Maybe on top of the dash or on the passengers side? We will figure this out!

What's in it now? It's not too late to send it back.

Based on the rest of your setup I don't really see the need for a bigger cam, with your manifolds and turbo selection you should ultimately be able to push in the 600hp range (you’ll be limited by your turbos, not your cam). In a perfect world, you probably should have gone with a slightly longer intake duration, more lift all around (especially exhaust if your heads will take more lift) and more lobe separation, it would increase your overall efficiency (in other words, a cam that would act slightly smaller in an NA engine).

Traditionally, you’d install a cam advanced to increase low end and responsiveness (a good thing on a turbocharged setup, since if you need top end you can make it by just letting the turbos keep pushing air), and retarded to increase top end. With the relatively small LSA and the rest of your setup you might find that you’ll gain low end responsiveness and top end by retarding that cam a couple of degrees (you really want your exhaust lobe closing as close as possible to TDC and the intake opening as late as possible after TDC up to the 20-30* range if there are any doubts about the restrictiveness of the exhaust side of your turbo setup). When it comes down to it I don’t think it’s worth messing with. That cam is small enough that you will be hard pressed to notice what advancing and retarding will do to your low end and your top end will be dictated by the turbos.

A bigger cam would be counterproductive with your engine and turbos, since it would accomplish nothing but move your power band out of the range that those relatively small turbos will work well in. Anything that would make you shift above about 5500 would cost you et.

I have a Comp Cam XE268H in it right now but everyone says that cam isn't good for a turbo. So I ordered one from Comp. Which by your description should work good and it tops out at 5000 rpms so I should be good to go by what your saying.

Brad...

what are the #'s on the XE268H?

Here are the specs.

COMPETITION CAMS CAMSHAFT SPECIFICATION SHEET

PART # 12-242-2
ENGINE: CHEVY SML BLK 265-400
INTAKE EXHAUST
VALVE ADJUSTMENT HYD HYD
GROSS VALVE LIFT 477 480
.006 TAPPET LIFT 268 280
VALVE TIMING OPEN CLOSE
AT .006 INT 28 BTDC 60 ABDC
EXH 74 BBDC 26 ATDC
THESE SPECS ARE FOR CAM INSTALLED
AT 106 INTAKE CENTERLINE
INTAKE EXHAUST
DURATION AT .050 224 230
ADVERTISED DURATION 268 280
LOBE LIFT .3180 .3200
LOBE SEPARATION 110
RPM OPERATING RANGE 1600-5800

THIS CAM SHOULD USE SPRING # 981-16

I wouldn't worry about running water to the turbos, it's not neccissary.

Cheers!

Wow, that's much bigger then I expected the 268 to be... must be that it's one of the extreme grinds, I was hoping that it was more like their old school single pattern grinds, which would have been more fitting.

To be honest, if it was my car I'd get it running with the turbos and then mess with the cam or whatever else if I came to the conclusion that it was really hurting me. Something like that cam probably would hurt what the turbo setup could do at the low end, but if your car is already setup with that cam in mind then who cares? You probably already have a decent converter, reasonable gears...

I think you will be able to make it if you don't mind crankin the boost up to close to 20#. It takes nearly 650+ crank HP to run 10's in the quarter at 3500 lbs. With a bigger cam it could be done with less boost yet more rpm.

What block are you running? I keep hearing that the 4-bolt GM factory blocks are only good for about 500hp.

I got my cam in last Friday also. We'll see how it works out. Spec's are:

Comp Cams
3316 intake lobe (236 @ .050)
3315 exhaust (230 @ .050)
on a 113 LS.

I was goofing off with DD2000, and the screwy program thought I'd pick up 100 hp going with a 280 exhaust duration @ .050. I don't think so. FWIW - this is going w/ the AFR210's, Accel Pro-ram, and a 4.1215 bore/3.75" stroke Dart Little M. I can't wait!

Hey Andris, I meant to say something on the 3rd gen list when you mentioned that before... but what is the point of even trying with DD? As far as I could tell their modeling for a turbo doesn't take into account that at some point a small turbo becomes a restriction, so it incorrectly assumes that if you pick the smallest turbo and let it keep running it will build the most boost and get the highest #'s (unless you've figured out some way to get it working anywhere near right)

I don't see any point in trying DD2000. I had the software, so I figured what the hey. They don't account for turbo back pressure. I called and spoke to someone once upon a time, so you can have infinite boost, and no back pressure. I'd like to try to model it in Engine Analyzer Pro sometimes, if any of you guys have the software and could do a quick test.

A.

:sillylol: I was thinking the same thing, I'm actually going a bit bigger, a 208/208 is going in this winter