Matt87GTA

I posted some stuff in the Hooker install thread on the Exhaust board, but figured some people here might be interested in this info.....

I hit the dyno with my GTA last week finally....

419.8 rwhp @ 6000
387.9 rwtq @ 4200

All of the specs on my engine/car can be found on my site (follow link in sig). These are off a Dynojet above ground chassis dyno in 70* weather here in MN.

This is definately not all that it has in it... I am getting some serious valve float. That combo should pull past 6500rpm easily and I have seen as much as 40hp between 6000 and 6500 rpm for Miniram/ZZX combos. The torque also seems a tad low....

I am not exactly sure what happened with the valve spring setup as I instructed my Brodix rep to have them assembled with the proper springs per TPIS for the ZZX with a Hydra-Rev as well (I think he said something like 380 over the nose with 140-ish seat but don't quote me on that). I might need to try backing off the preload on the lifters as well as I had them set at 1/2 turn past.... My plug gap was pretty big as well (.050"). Lots of little things to play with before I head back to the dyno early next month. I will start by pulling a spring off and having it checked out.

I suppose b*tching about pulling over 400 rwhp would be considered whining, its just that there is more waiting to come out.... And I must find it .

RB83L69

Good numbers!!!!

The MiniRam is definitely the way to go for a high-power FI motor. I fail to see why people even bother with any of the LTR setups.

You probably don't want to know why I'm saying that.

That's definitely not enough valve spring to be trying to make real power at those RPMs. It's really not enough seat pressure. You should really consider losing the hydraulics and going to a solid roller. You're going to be fighting a losing battle with the hyd setup.

IROCZZ3

Very impressive numbers!

What kind of lifters are you using? Comp R's??

BadSS

I’d definitely back off the lifter adjustment before pulling the springs. Try them at 1/8 turn and see what kind of rpm you can get. I'm running pro-magnum hydraulic flat tappet lifters set to 1/16 turn with 105# seat pressure and 310# over the nose (417# rate) springs and have zinged it past the normal 6400 rpm shift point a number of times without problems. The G1 TFS 2.02 valves are a little shorter than typical SBC valves, which mean they might weigh a little less than your valves,,, but I’d think you should have plenty of valve spring pressure (along with the hydra rev kit) to pull a little past 6500 rpm. That is,,,, if the springs actually rate to specs and there is not a control issue with the lifters.

Matt87GTA

I put a new set of Comp OE replacement lifters in.... the 850s when I built it and it has all of the factory roller setup stuff in it along with the hydra-rev kit. The Comp Rs were on mega-back order when I put this thing together.

Yeah, the lifter preload is really something that everyone I talk to has hit me with but I think checking a spring will be a good idea regardless.

I have toyed with going to a solid roller a few times but I just got this thing on the road again and really don't feel like tearing back into it just yet. There is definately more power in a solid roller for this engine - the intake, exhaust, heads, and lower end are all good to go for much more. I also have a good .020" and .122" to play with for piston to valve clearance as it sits right now without fly cutting the pistons at all (assuming a minimum of .080 intake and .100 exhaust minimum clearance)... Although a solid will have much more aggressive ramps.... Bahhh.. maybe this winter or something (if I'm still stateside that is). Probably have to look into more compression with a more aggressive cam as well (it's at 10.7:1 right now).

Thanks for the compliments and input .

89gta383

iTrader: (5)

:hail:

Matt87GTA

So.... ahhh..... Why are you saying that anyways????

89Warbird

I'm impressed!!!!

:yourock:

RB83L69

There's other stuff to go with it; it's eventually going on a 400 block, with some aditional stroke.

camarojoe

Wow, Matt, those are great numbers. Those are more like what I was expecting to see. I see you peaked at 6000, when it should be 6500 like you said. My hp hit 376 at just under 6500 rpms. Your car has a stick right? That will give more power than my setup, which is almost identical, but you've really got a lot left as I hope I do. I'd love to get ride to the dyno again, it's been down for more than a month. I do have a couple of questions, though concerning the chip. What is your max total timing and where do you have it come in at? I was having some concerns on where my timing was at in my chip as I didn't get that far yet.

Joe

89gta383

iTrader: (5)

I'm swapping cams and hope to hit your numbers myself. Don't know if I will go with the ZZX cam yet, I have a call in to Bauer Racing, Advanced Induction, Lloyd Elliot and others for a quote.

I'm thinking something around the XE lobes 236-248 .593-.600 on a 110 lsa would make some decent power. Comp said if I wasn't on the bottle to run it on a 108 lsa. I just picked the lobes out of the catalog, so I might not know what the hell I'm doing, but on engine analyzer it picked up 25 hp over the cam I have now. I'm also thinking about the XE 242-248 on a 110 lsa. don't know yet.

Maybe I'll get this thing running soon.

Damon

Matt- good numbers. Very similar to what I got with a 400 under a Miniram. I had a lot less cam and a few more cubes than you so my HP was about 20 fewer but with more torque at a much lower RPM. The way that Miniram stretched the upper RPMs of our tiny (210/210* @ .050) cam was just amazing. If you waited for the torque to fall off before you shifted you'd bang the 6200 RPM rev limiter every time. The torque curve was a billiard table from 2700 to 5000 and then tapered off gradually.

With a bigger cam (224/224 @ .050) it was an ANIMAL up top and still had plenty of torque to carry the stock converter and stock gears down low. Never had it on the dyno with the bigger cam, though.

This engine was put up against a 400 HP ZR-1 Corvette from a 70 MPH roll on the highway (with the bigger cam installed) and just walked right away from it up to 130 MPH.