I got my car dyno tuned today and ended up finishing what I thought to be way low from what I normally read and see in this section. The motor seems to run mechanically fine its just not putting down the power I thought it would. Mods are as follows:

6.0L iron block
30lb SVO injectors
Pacestter longtubes with offroad Y
Hooker Catback
Comp Cams XER 238/240 with .605/.609 lift on 112 lsa
Patriot Peformance Stage II LS6 heads with oversized valves
Fast 90/90
SLP MAF
SLP lid

The final result was 412 hp and 398 tq on a dynojet. This is an M6 car with a stock 10 bolt and 3.42 gears. It was 92 degrees out with approximently 30 percent humidity. I just though I would be closer to the 450 range with my setup. The car runs fine and has a 13-1 air fuel ratio for the entire curve. The torque curve is very flat. Just seems like everything should jump up by at least 30. I'm gonna try doing a compression test on each cylinder here shortly.

 

Way too low buddy it seems like a cammed 346ci numbers so do the scan & see what ya come up with & if theres a dyno graph it would be better !!!

peace

 

I also think it looks a bit low, but I'm no tech expert. I'm sure there are people here that will be able to help you though.

 

What is your compression ratio? Stock shortblock or built?

 

something has to be wrong somewhere,there are 346 ci engines with cams that size pumping out around 460.hit the track and see what mph you lay down.maybe try a different dyno just to see if that is the problem. i know dynos are just a tuning tool but they do prove your engine is up to par .

 

The engine is the stock short block. It had about 20k on it and the rest of the parts got slapped on it. The heads combustion chamber is 59cc I believe, so I should be somewhere around 11-1. The tuner called me today and told me he thought about it all weekend and wants to redo my car. He said he had to take a lot of fuel out and there were other things he could do instead of just taking fuel out. The car seems to run fine. I really was hoping for 450ish. The car seems to run a little rich still. Smoke out the pipes at idle. I think the idle could be adjusted some, but I dont see how that would have to do with WOT power. Anyone have a similar setup and tune their car with tunercats and could send me a file.

 

I went back to the dyno today. Tried to go a little different route on the tune. Then my car sounded like it spun a rod bearing and all hope was lost. So I never tried to take the engine out of the car in my garage before, but I guess you gotta do what you gotta do. So is the car telling me to go forged or 408 who knows...

 

i have seen some patriot heads put up lower than expected numbers

 

Most of my buddies have had pretty good luck with there patriot heads

 

patriots heads are getting better from what i have read

 

What happened to all the previous 450rwhp patriot headed setups. Thats what made me decide to purchase an F-Body. Im talking before any other heads were avalible besides factory whittled castings . Remember the hype on the first AFR's before they were released ,yeah those were fun times. I read up and didnt even own a F-Body yet, but I was hooked. I dont understand the lower power numbers of today in general. The last post I remember on the commonly used Patriots was a disappointing number and all great numbered patriot setups vanished. Not knocking the comapany cause the prices were incredible for the powerlevels little 2 gs for heads and cam kit . I came from a 200rwhp 5.0 mustang so 450rwhp looked astonishing to me , hell still is. ....Their are so many options now for us that I get dizzy benchracing my future setup . Good Luck with your future build. Patriots have large Intake port cc's so get your DCR up as much as possible .

 

Am i correct in assuming that you want small intake runners?

 

Our intake runner volume is 227 +/- which is much smaller than other OEM ported 243 castings on the market. Most of which are 235 and larger. We add approx. 65-70 cfm of flow while only increasing runner volume by 15cc over stock. Our current program flows 302-305 with a 2.02" valve.

 

My motor had some issues so hopefully with a different tuner there is some good power to be made after the rebuilt since i broke 2 pistons

 

I heard from a little birdy that this motor made 492 rwhp in a 97 c5 a few months ago with kooks 1.875 and open 3 inch y pipe and a different tuner. I think the patriot heads are going to be just fine.

 

Well, just poking around on the internet and checking some of the boards, I run across this thread that sounds just like a car that blew up on my dyno. So let me give everyone the rundown. Customer comes in for a tune on a head and cam 6.0. Says him and a buddy built it. Should have a cam "a little over .600 lift", CNC heads, fast intake. Injectors are FMS size XX. Also says him and his buddy "tuned" it as far as displacement, injector size, yada, yada. So we run it and it puts down 390 and about 366ish(photos and graph should be up in a little while). We squeezed 412 and 398 out of it, but something wasnt quite right. Now, let me back up a little. The displacement WASNT reset, nor was the injector size, so i put them in on the initial tune and we went from there. After thinking about it all weekend (sound familiar stocker?) I called the customer back to come in for a redo, again I knew something wasnt right. On the second go 'round, she started knocking. Upon disassembly we found EVERY VALVE WAS HITTING THE PISTONS. Not just one ALL OF THEM. Pictures coming. Brought customer in and showed him. He said his buddy fly cut them. Told him what the cam was,PN XER281HR-12. Specs are as follows:232/234@.050,.595,.598, 112LSA. Heads were patriots with 2.055 intake valves and I dont remember the ex size. Now keep in mind we're tuning something someone else built. So now even after I tell this guy what cam he has, he's on here telling ya'll something different. And after building an engine, he wants to know if a tune could reduce the PTV clearance. WTF? And how does the tuner get blamed? A "better" tuner could have popped the motor just the same. We tune some of the sickest **** in our area. LT1s, LS1s, SC, NA, blown big blocks, Accel DFI, FAST,SCT(mustangs) with SCs, turbos, etc. I'm more than capable of tuning this thing. This is the problem with tuning stuff that other people have built. And nothing worse than being blamed for someone else's incompetence. I guess we found out why its not making any power. Bangin 16 valves onto 8 pistons has to hurt the output just a little. Will be posting pictures soon. Notice the burr around the eyebrow? Everyone of them looked like this

 

I'm sure there's more power in this combo, just needs to be built right. And why arent we dealing with this off of the internet? This is NOT a tune issue. It is a BUILD issue. Just trying to clarify.

 

That was the story I got when the car came in initially. After we tore it down and found ARP rod bolts in it and bearings that looked brand new he tells me him and his buddy went thru it and even said his buddy fly cut the OE hypereutectic pistons (see pictures). So which one is it? How about taking responsibility for the lack of PTV clearance and we can all get on with it.

 

Well my posts werent meant as an attack on you edcmat-l1. I never stated it was your fault or the tune. I just was trying to learn a little about it all. As for the cam specs, i dont remember if you told me you called comp and ran the numbers or not but that is what i was told was in the car. I was not trying to bring discredit upon your buisness or anything. I'm just pretty scepticle about getting the car tuned again. Ive been running a couple different threads on here to try and get some answers to some questions I had regarding tuning and about going with just forged pistons as opposed to forged pistons and rods. Never did i say anything to bad mouth you. So I hope we can all get along.

 

Actually you were pretty decent about it, not bad mouthing us, that is. A couple points though
1: I showed you the part # in the comp cams MASTER CATALOG with all the specs. Should have been no question at that point.
2: You have continued to insinuate (typo?) that its a tune issue, stating that you want to have it tuned by someone else.
3: You changed the story a couple times as to what you knew about the motor.
4: I havent seen you take any responsibility for what happened to your motor. I hope the pictures are clear enuff for everyone to tell whats up.
As far as the rods are concerned, they're good for 500 HP with just rod bolts. You have ARP bolts in them now. Would H-beams be better? Of course, but you've said you where on a budget. BUT, if the piston to valve clearance isnt correct, it doesnt matter what you put in it, it'll live a short life. As far as tuning it, it wont leave my shop without being properly tuned. Afterwards you can take it to whoever you want. I dont lock my tunes, so anyone can look at it and tell you if I fucked up or not.