TheCarKid

heads are unmilled. I don't remember exactly i don't have the receipt any more but the head gasket thickness is either .040 or .045. Not sure sorry.

NoGamesLS1

iTrader: (16)

Looks like your somewhere between 10.2-10.4:1 The only thing I can think of is the ls1 intake. Hey if you ever have to take off your heads get them milled alot! Its free hp I have a trex and am 12.5:1 and run CA 91 pump gas

TheCarKid

I'll see how much hp a new intake will let loose. And if I do take the heads off I'm definitely getting them milled. I should have done that before I put them on but I completely forgot about it.

NoGamesLS1

iTrader: (16)

Ya try the intake and maybe port that tb a little. Good luck

Studytime

iTrader: (15)

He said LS6 heads and a thinner gasket, so I think it's a safe bet so say compression is >10.55:1.

Ben T.

TheCarKid

I think i'm gonna go with the typhoon intake w/ a 96mm tb so i don't think i'm gonna have to worry about porting it. lol.

DuronClocker

iTrader: (25)

And when you buy your intake, buy some new injectors. You're running out of fuel up top, and that's only going to hold you back from making more power with a better intake. If you're buying from Speed Inc, buy their 38# injectors. They told me to buy the 30#s, which work great for my power level, but I have absolutely no room to spray a decent sized dry shot and keep my duty cycles in check Plus, the 38's are $20 cheaper I'm assuming the 38s are SVO, but if not, pick up the 42#'s for the same price as the 30#'s. There won't be any problem tuning idle with those, and they'll allow you to make all the power you can possibly want NA.

And seeing a T-Rex peak HP at 6200RPMs means your intake is holding you back big time. My car made 421/400 through my Magnaflow on their dyno and I have a much smaller cam than you (though I had an LS6 intake at the time). On the flip side, the 4.10 gears are taking away probably close to 8-10rwhp and I also have a U/D pulley and at least another 1/2 point compression.

EDIT: Even my peak TQ occurs at a higher RPM, which is interesting. Definitely change the intake first. Wish I'd had seen this post about a month and a half ago before I sold my LS6 intake. Would've let you bolt it on before buying it to see if it fixed your problem :doh:

wavrdr

iTrader: (1)

I'd say remove the heads and mill as your DCR is on the soft side, and make sure you're running a Cometic .040 for the quench. You already have the valve reliefs in your pistons so PTV should not be an issue.

Get your self a ported Fast with accompaning tb/injectors and get the car retuned....it will be a comletely different animal!

Good luck!

pianoprodigy

iTrader: (1)

Wow, I knew the problem before I even clicked the thread...I won't comment though...yet

losiguy

iTrader: (7)

LS6 intake, and mill the heads .035".

brad8266

iTrader: (23)

The intake is killing you badly. On my bolt on car the Ls6 made a significant difference on the top end. The LS1 mani flows air bad up top which is where a cam like that is making all its power at. Get an LS6 or a FAST and you will see a huge improvement.

Milling the heads isnt going to really gain you any peak numbers but it will help out down low.

moeZ28

iTrader: (7)

Professional Products 96mm throttle body isn't out yet. I called Byunspeed the other day and they told me it would be a long wait for that product and tried to sell me another throttle body.

orangeapeel

iTrader: (18)

That is what my 347 graph looks like with heads and cam, but it is the 224/230 A4 and nitrous rings with retarded gaps that is doing it to me. Everytime it goes onto the dyno...I get blowby that makes people think that the car is on fire.

DuronClocker

iTrader: (25)

Are you running stock pushrods?

kossuth

iTrader: (12)

Well, before you just go and start buying parts I'd do a leakdown test. It will give you an indication of your motors true effiency. Did you put the motor together yourself? I'm not saying there is something wrong with the motor, but it wouldn't have been the first time a set of rings didn't breakin and seat right for some unknown reason. I agree that LS1 intake is costing you where you need the air the most, up higher in the RPM band. Hell, you could see if the rest of the motor is matched up right you might possibly be leaving close to 40 hp if not more on the table. Every part has to be matched to each other and I'm not convinced yet that the motor is 100% right. Personally, unmilled LS6 heads are not the way to go. Your dynamic compression is low enough because of the overlap of that cam. Thus you need to run more static compression. I'd aim to have at least 11:1 statically. Also, how much were the pistons out of the hole? If you put the motor together did you even check this? It wouldn't have been the first time I've seen pistons that have had the wrist pin machined in the wrong spot. The pistons should be close to .010 out of the hole. That effects your compression. Being this is a new motor, I'd like to know all the variables rather than just taking a half assed guess. I'd hate to think you possibly taking my or somebody else's advice and spending your hard earned money to not completely solve the problem. Being this is a new rebuilt motor I'm suspect of it.

99blancoSS

iTrader: (115)

Lot of over blown explanations here for the real problem being the ls1 intake

Do yourself a favor and replace your intake before you do anything else.

Then dont get caught up in the over blown theory of having to have the perfect dcr to make power.

Only problem with this guys setup is the intake but you've got people here telling him to pull the heads. WTF?!?!?

You could check the compression real quick to rule and it wouldnt be a bad idea. You dont need a leak down test just buy a guage and foillow the instructions. If there is an issue you'll see it. I was having an issue with being down on power and simple conmprssion check chowed me I had 180 psi in all cynlinders exxcept for one wich had 60psi.

Regardless of what you find with the compression check you still need at least an ls6 intake with a cam of any size.

Also new injectors?!? where on the a/f graph do you see him going lean on his dyno run? stock injectors are good to about 450 rwhp

This guys problem is the intake

Cam02ss

iTrader: (8)

get rid of that LS1 intake. mine put down 463/402 on a mustang dyno with a Rex, GTP stage 2+ heads and a FAST 90/NW 90 TB and the other usual supporting mods.

Orange Juice

iTrader: (3)

As has been said. Intake, compression and quench all will play a big part in the number that you get.

Patrick G

iTrader: (14)

Your torque curve looks like the cam was installed perfectly. The curve looks perfectly normal, but it's obvious that you're starving for airflow up high. If you've got the dollars, the FAST 90 is worth the money when you're running a cam that big.

TheCarKid

well that's no good.