Just like it says...you guys pointed me in all the right directions throughout my re-build but now it seems i'm still dead in the water......re-built LT! with cc305, AFR 180 heads, stock bottom end re-build- re-built trans with 3000 stall, 4.10's in the rear. Also just got dyno tuned and that showed a 60 hp jump- 314 hp at the wheels(which still seems low). Before any of this when i got the car and minor bolt ons i was consistantly around 13.6-13.8 at 99-100. Now with all the mods and re-build and tune- last night ran a heart breaking 13.8, 13.9, 14.0. Had some traction issues but come on! Shouldn't there be more. Was thinking on a good day with good traction i would see high 12's!!!. Is this not going to happen with my set up.

 

im not a master at this, but your hp does seem a little low for the work that is done i would think more like 350hp to the wheels and seeing high 12's-low 13's

 

Exactly.......I'm looking for what could be holding me up now. I need a starting point again

 

3000 stall with 4.10's with the cc 305? Correct me if I am wrong but doesnt that cam only go to about 6300rpm? your set up seems more idealy suited for like a 847 that like to go to 6800.

Lets see, do ou have stock injectors or a stock fuel pump? Rocker adjustment? Check temps on header primarys so you can see how the motor is running. You didnt say anything about it missing so I wont think about that, any KR?

 

....847?....need more info. YES- everything related to the fuel system is stock. And what temp should it be at the primarys if its running correctly.....and no nothing seems to be missing. Could it be the set up is incorrect.....i was thinking that it was the wrong cam......or not enough cam....

 

AFR 180 heads? why? you couldve gone bigger and got alot more out of your setup. 190 or 210, which wouldve been my choice, would work better in this setup.

 

180's because they were there. I see now that i could've gone bigger- the 180's can be improved right? is that where my power is being lost......

 

847 Is a cam, its a factory GM cam made by crane. Its relative to the cc 306 but it is still bigger. You may want to look at upgrading your fuel system. I would look at 30lb injectors and a walbro 255. You said you got a dyno tune? What was your a/f? It may just be running out of fuel. You never said if it had any KR(knock retard). And I agree with whoever asked why you didnt go with afr 190's. But dont think that the 10cc diffrence is holding you back like this.

What are you shifting your car at?

Do you have RR? What about your valvesprings?

See if you can get a fuel pressure gauge from an autoparts store and hook it into your test port at the back of the intake and then tape it to your winsheild and go drive the car and get on it, your fuel pressure should stay above 40psi. I am not sure what stock fuel pressure is on our cars, I think its ~43psi at idle.

 

No! Those heads flow more than stock heads and I've seen 330rwhp from bolt on cars with the hot cam kit. Your cam is bigger than that with better heads. Something else is wrong. Did you break the motor in correctly? Compression check to be safe?

 

As far as the dyno sheets i have to go check them out...be back later with that........Do i need bigger injectors..i was told stock injectors were fine....and fuel pump possibly needed to be upgraded at this point....shouldn't both been done or nothing at all? RR are 1.5's cc......knock retard- i'm not to familiar with it- but it has something to do with valuetrain noise right?.....is this something i would feel or something diagnosed in a dyno tune.

As fas as breaking in the engine...it had an easy first 3000 no wide open throttle racing.....no lon trips at a steady rpm.....this is what i was told not to do when breaking it in.....will compression leak down test tell me if its not broken in right?

I appreciate all the feed back i just need to check on some things to answer your questions to me...again thanks for the help..after last night's numbers i almost bought a for sale sign......but i'm sticking with it......

 

Knock retard can be checked with a scanner. What it does is if the knock sensor in the block picks up any strang noises it will pull timing from the motor and that hurts performance. I think you need a LT4 Knock Module if you dont already have one. Not only do you have RR but you have a cam. The KM is located on the back of the ecu. There only like $30 off ebay. I would look at you fuel system. The potential power you could be making is to far for your stock injectors I think. Get some SVO 30lb injectors and a Walbro 255. The pump is like $110 and the injectors can be found on ebay for $100~150. And then you will have some room to grow afterwards b/c I think the pump is good to ~550rwhp and the injectors can go over 400rwhp.

Get a scanner and hook it up to you car and see what the motor is doing by looking at your sensors, look at your O2's make sure there reading right. Even though you dont have a CEL doesnt mean something isnt wrong.

Maybe you got a bad dyno tune?

Most important, Dont Give Up!

If I can go through 2 motors in 4 months(out of my control, just my luck) and over $2k and still keep going than you can too.

 

I was told by the tuner that the car was way below on the timing. He added more timing to improve performance. Wouldn't there be a (red flag) on a scanner that would indicate knock retard to him. Another words should he have fixed that already.

Fuel system seems to be coming up alot also. If i first checked the fuel pressure while driving and it tells me pressure is where it needs to be then as far as fuel goes its ok for now right? Must be something else then right?

Again thanks for the imput

 

Your injectors should be fine... i think stockers are good to over 350 rwhp or more. Your fuel pump however may be dying on you. That would cause a dramatic loss in power. Also are your roller rockers adjusted right? Make sure you get a lt4 knock module because the stocker will detect way to much knock with rrs and headers(you do have headers dont you) and pull a crap load of timing.

 

Tuning question- If i just got a dyno tune and he put a bit more timing into it but didn't eliminate or collobrate the knock modular (first of all does that even make sense doing that) and if i continued to race the car would the knock modular pull timing again even though it was just programed to have more timing?

 

Yes if you dont have a lt4 knock module or some tuning to desencitize(sp) your stock one, then you comp will be pulling lots of timing and will be really low on power. GET THE LT4 KNOCK MODULE, it is worth the 30 or 40 bucks that it costs.