I guess this is an open invite for criticism, but looking at my dyno sheet and comparing it to the stock motor i notice a very large difference in the torque curve. It is now much broader (more area under the curve. Before (stock motor) the torque peaked at 3200 rpm, now the peak isabout 4200 Rpm. The Hp peak was at 5200 on the stock motor and now its at around 4700. The cam was supposed to make power all the way to 6000, I wonder if there is something holding it back. I know the MAF maxes out right around the point of MAX Hp, but the A/F stays in the range i want (around 12:1) but it usually takes a rich dip right after maxing. What do you think. I should have the dyno sheet up by tonight

Bill

 

http://www.bytehead.com/~dunk/dyno.html

Dyno is posted, let me know what you think.

Specs of the cam are: 224°/220°, .544"/.544" lift, 114LSA, +4°advance

I would have thought the peak power would have been a little later in the RPM's with this cam. Let me know what you think

Bill

 

I'm also suprised that it peaked that early with that cam. Mine peaks at 5,500 with a 214/222 cam.

You're sure that there was no drop in boost?

If you had solid boost control, my next guess would be that there is a restriction somewhere???

 

Here is the cam Duttweiler recomends for my twin turbo 355 89 camaro. 232/232 .515/.515 114/114. This is a flat tappet cam going in my 4bolt 355 with all 4340 internals. I was realy confused on what to run and this is what Duttweiler recomends so just to give you guys a little more info to look at. I'am running 8:5:1cr, AFR190 heads and two t3/4 turbos, 3" down pipes hedman s-10 modified headers 1 5/8 and stealth ram intake. My motor is currently being built. I plan on putting two pt52s from precsion on this winter to try to make 1000hp. Kenny said i should make 800-900hp with the hybrid turbos and this cam and be a very tame mannered street cam. I'am no expert just wanted to pass along some advice i got from a very respected turbo guy.

 

Like INTMD8 said, are you sure boost didn't drop off passed 4500rpm? It's interesting to note that the rise and decay rates are very similiar.

 

I'm positive the boost didn't drop off. It rose steadily up to 18 psi and stayed there around 5500 rpm. I have an exhaust leak, but it wasn't major, just enough to hear it at idle. It got a little worse as the number of dyno runs went up

Bill

 

My guess would be the cam.

 

Nice!! Intresting to see the difference in power bands in a turbo v8 and a turbo i4. The torque is ungodly for you all I like your choice in turbos and standalone.. I too use a precision turbo pt74 and a Speedpro system Once again nice numbers!

 

that is with 1.6rr too

ask me how i know

I have the same cam in my motor

 

If you look Smokinz advanced his cam +4* which is going to cause the power band to shift to a lower rpm than would normally be the case. Advancing causes the peak hp/tq to come in sooner and retarding the cam causes it to come later.

 

I think the manifold is whats causing it to peak so early. The volume of air is just to much.

Jose

 

im deff with Jose on this one I think your manifold is a huge restriction on the power.

There is a local stang racer who went from a tt log to a header system and gained like 80-90 hp forget exact amount but the only change was the headers. The tt system is good for what it is for a mild street stock setup. When you get into bigger hp your choking yourself with their small manifold and cross over etc...

Have you thought about moving the wastgate up front by the bend down for the turbo? I was going to do this when I had their system (also some other things)but my focus changed...

Steven

 

Steven,

I have no plans to stick anymore money or time into this system. Its really not worth it. I like the kit, but i would have to do more modifications to get it to where i want it, and i really have my eye on an all tubular system. Everything on this kit is rigid, with the exception of my wastegate vent, and it just weems to like to leak everytime I get on it for extended periods of time probably due to expansion. A flex joint on the crossover would work out nice. moving the wastegate wuld be nice, and then a bigger crossover would be nice too, it just keeps going. And the slipjoints, especially the one on #1 primary is leaking like a mother. I'd like to weld it back up, but it would be a shame to have to grind off my nice ceramic coating. I guess all I'd like to do is make the most i can with the system and sell it this winter for a pro turbo kit. Thanks for the input guys.

Bill