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Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 9:59 am
by CamKing
A legal 602 will only make 350hp. It only has a 212/224@.050" Hydraulic flat tappet with .435" lift.
The built engine should make over 400hp(We were making that much with a hydraulic cam).
If hooking off the corner is a problem, that can be fixed with the cam.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 10:50 am
by dirtracer
Mike is correct on the hp of the crate. What heads did the motor have that made over 400 with the hydraulic cam?

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 11:01 am
by JDR Performance
The power you see with a 602 depends on a few other things. The carburetor, headers, collector length, fuel, spark plugs, and where the timing is set will make a difference. I've got a stack of sheets here and just as a recent example a 100% legal motor straight from GM at the end of last season went 376hp and 404tq uncorrected. 400/430 with correction. That was the first pull. Where it ended up was better yet. On the other hand, there are several builders that are over 400 to 420hp with a gauge legal 4412, and over 400 tq. with the fully legal Sportmod motors. Camking, I referred one of them to you and will ask him if you guys got together on it.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 11:24 am
by dirtracr5
we've seen the same thing around here in the sportmod class. crates win alot. anything from big fast 1/2 miles to 1/4 bullrings. the open motors do ok as well. i think the rules they have now give both motors and equal shot.

last year when the hobby stocks went to crates they were flat out dominating! same engines rules as the sportmod with the exception of cast exhaust. also the hobbys ran a 2bbl on the crate not the 4bbl like the mods and they still cleaned house!

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 11:28 am
by CamKing
JDR Performance wrote: 100% legal motor straight from GM at the end of last season went 376hp and 404tq uncorrected. 400/430 with correction.
You need to have your dyno checked.
We've dyno a bunch of them striaght from GM, and they have a hard time making 350 corrected, and the dynos in this area are not known for being on the low side. :wink:

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 11:31 am
by robert1
He uses those special springs! :wink:

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 12:10 pm
by JDR Performance
The results I have are from different dynos across the country. The one I mentioned was on the stingiest of three dynos in the area, and the 2bbl Sportmod motors are going on the same dyno. You haven't seen any difference in power output with different fuels, carburetors, timing, or headers? Believe it, don't believe it, whatever works. Maybe all the dynos need to be checked.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 12:20 pm
by CamKing
JDR Performance wrote:The results I have are from different dynos across the country. The one I mentioned was on the stingiest of three dynos in the area, and the 2bbl Sportmod motors are going on the same dyno. You haven't seen any difference in power output with different fuels, carburetors, timing, or headers? Believe it, don't believe it, whatever works. Maybe all the dynos need to be checked.
We have to run the 650 carb, and the track fuel.
The cam is only 212/224 with .435" lift. You can't make 400hp with that

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 12:25 pm
by JDR Performance
IMCA can use any Holley carb, billet metering blocks and base plate allowed, and "race gas". No E-85. If you talk to people racing IMCA there is a good mix of people winning. Some with crates, some with the 4412 motors. If one had a huge advantage over the other you wouldn't see that.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 12:42 pm
by JDR Performance
BTW, for the record I'd rather see people spend their money with engine builders but it is what it is. All you can do is provide the best parts you can for either one.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 1:07 pm
by IMCADW
Glad we have some insight finally.

As a driver, whom has raced the "A" mod or Open class in IMCA for a while, I know the benefits that gearing can do for you. I also feel that the motors are close and it's preference what you run. Personally, I'm a gearhead. I like to build my own stuff, tune and fix. I believe the advantage for the crate is reliability and ease of care. It's pretty simple, and there's not much you can fix if it breaks. The claim motor, you can gear the heck out of it, trail brake your car on entry to gain 2-3 car lengths, and roll the center better with the gear.

JDR, I hear a lot of good about your 2bbl 4412's. Keep up the good work.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 2:16 pm
by CamKing
Just checked to see what we're making with these same rules. My customers are all in the 415-440hp range. No 602 will keep up with that.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 2:45 pm
by Brian W
Just got a 100% legal, straight from GM, 602 off the dyno. Was setup for IMCA hobby stock with cast Ex manifolds and a Roch 2bbl carb. made exactly 300hp. I have a 100% legal IMCA hobby engine that we put together on dyno now and will be running it in the morning. Will post results when I get them. We will be testing several different combos with this engine, different heads and Ex manifolds and pipe size... should be in for alot of learning!!

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 3:00 pm
by raceman14
Looking at the rules I must be missing something.
Built engine gets :
As good or better head choice
Better intake manifold
Open flat tappet camshaft
No RPM limiter
Any race gas

Limiting factor is the 4412 in comparisons it should flow close to 400-425 cfm compared to a 650HP flowing 600-650cfm. Engines will usually have the possibility to make 1hp per carb cfm flowed on my Superflow bench. I have verified this from 5HP Briggs, Animals, Nascar 2-bbls, ARCA, BGN and CUP engines.

There are usually other limiting factors that can make numbers higher or lower. 602's are weak on cam, lifters and springs & intake manifold and of course the 6200 rev limit.

That engine built properly should be a minimum of 425hp with an out of the box 4412.
With a good 4412 and minimal legal head work, good headers and VP-CHP that engine should go 475hp and turn 7500rpms.

Re: 602 GM Crate vs. Built Engine

Posted: Fri Mar 23, 2012 3:02 pm
by JDR Performance
Thanks IMCADW! Mike, I'm not disputing that some dynos are cranked up. I have seen that the legal Sportmod 2bbl and 602 motors are pretty close on the same dyno. For the sake of a good conversation, if you're seeing the 2bbl motors making 65-90 hp more than the 602 motors on the dyno you use, that would put them close to 465-490hp on the dynos other people are using. If that can be done within the rules per your suggestions these engine builders will be singing your praises. I'll send them your way and see where it goes. If they can make gains like that it would be great.