I am far from an expert but I really think that the 112 LSA on your cam is really killing you. Everything else about it sounds great (duration, split, lift) You put that same cam on a 116+3 LSA and I think you'd reach your goals or be really close.

 

He is running 1 full point less compression than stock motors.... Would that make much difference?

 

I think I found your problem...

 

Yes, you are right. You don't really need lower CR to handle the boost from the MP112. I also think his cam is has too much overlap for his combination. With good heads, I'd like to see it what it does with about 8* less total duration on a 115 LSA.

Phil, is your Blazer home yet?

 

why do you say the 112LSA is not good? can you explain? i'm very interested in your theory on this. thanks.

 

maybe a 122 or tvs is in your near future

 

A general rule is a supercharged cam will have little or no overlap (the period during which both the exhaust and intake valves are open simultaneously). Bleeding boost is the common issue associated with this and hurts the peak output unless you have the ability to jam more psi into the engine. I run a 115LSA 216/222 .552/.559. Look at the GT-2 cam specs and see why it is a good choice.

 

Yeah, i understand that, but thought maybe i was missing something on this cam. I thought that since he's still making 7-8lbs he can't be bleeding much boost off through too much overlap as thats about all the boost i see on a stock motor with a 2.8 pulley with the 112. So i was very curious as to why no one was liking the 112lsa? it's obvisouly not causing him a problem with boost bleed unless he would be making 10lbs with a 115lsa cam which i doubt...

 

I warned him. He is another beast, no wideband in the scans, using narrow bands to tune a blown motor. He has traction issues as well (12.7 @ 107). That thing has has a 12.4-12.5 for sure. I am just scared to lean it out...over email with only NBO2's for real time reference.


I completely agree with krambo. I had little if any IAT help from meth. I could get a few more degrees out of it, but nothing worth chasing. Or nothing worth trying to run it on the street and filling that meth up all the time.

460hp and a 12.3 is freaking awesome. I think your numbers look great cyazo6. With a stock Hxr I could hit 180* easy on a 1/4 mile in 80+* outside temp. Now I close the 1/4 mile under 165*. I run 19* religiously, don't pull until 170*. 19* the whole 1/4 mile, usually.

As far as that idle, mine is a 224/228 568/571 114, it is still a work in progress due to my lack of tuning knowledge . But pretty stable between 850 and 900.

 

Holty - He is running a 5.7L motor and a 2.8 pulley, not a 6.0L. All things being equal, he should see more boost pressure. Having ported heads should lower boost a bit, which is fine if its paired with the right cam. I'm pretty sure the C5 guys can get 10psi on their cars.

I think with that cam and ported heads, he is getting too much flow and too much of the charge air is going out the exhaust valve before it gets closed. With a smaller cam that has less overlap (time when the intake valve is open before the exhaust valve closes), he would see higher cylinder pressure and make more power. Another benefit would be the much better idle quality.