Chris5k

F-bird.. trust me i know about dissapointment haahah did you read my first post :P here was my thought... which obviously is what you told me to do except the catback

sofakingdom

iTrader: (1)

¿Cut?

Why?

If it fits, just use it.

Yes the right Hooker cat-back will support FAR in excess of 300 HP. Get the 3" one and just bolt it all up.

A vacuum leak CANNOT cause a problem with low power at WOT, because at WOT, there is no vacuum to leak. Plus, you have these 4 GIANT vacuum leaks at WOT, called THROTTLES, anyway. But vacuum leaks CAN DEFINTELY cause all manner of other driveability problems, especially at or near idle, when vacuum is high (meaning, even a small leak will let in ALOT of extra air) and the engine's air consumption is low (meaning, even a small amount of extra air has a HUGE effect).

Jetting is going to be the next major improvement. Everything else, besides just repairing defective stuff like gaskets or whatever, is comparatively minor.

Dialed_In

iTrader: (3)

Are you f'ing kidding?!

Any un-metered air is going to throw off the a/f. Not to mention a manifold vacuum leak is going to throw off the signal to the carb. That will affect every single aspect of the car's performance.

sofakingdom

iTrader: (1)

No I'm not kidding.Not WOT. A vacuum leak has to be of comparable size to a throttle bore in order to throw off WOT.

Idle, cruise, part-throttle, OH YEAH a vacuum leak will screw those up, big-time; but not WOT.

Chris5k

Sofa, I didnt assume that those small vacuum leaks would cause a major problem... so please just ease up a bit, I am young and I will be the first one to admit that I have alot to learn, I really appreciate all the help so far guys, just dont start flaming me like im a retard lol. My main concern with the idle adjusters was they are among the few fuel leaks that i have on my brand new $200 intake.. sorry i didnt mention my concerns with them more... but yeah the wrong spark plugs info really helped I was really not thinking there.
Like you said Sofa, my next step is to jet up, since im low on cash and have a BG jet set.. couple more bucks for gaskets and im good to go.

sofakingdom

iTrader: (1)

Chris, nobody is flaming you .... speaking strictly for myself ... rather, think of it as refuting inappropriate advice you are being offered, that will only divert you from the direct path to a solution.

Just keep doing what you're doing, concentrate on the tuning issues, and see how much progress you can make.

Dialed_In

iTrader: (3)

A carbereutor runs on vacuum. Any time you alter the vacuum signal to the carb it's going to affect it's performance.It's un-metered air, no different than a vacuum leak after the MAF on a EFI motor. If you think otherwise then you need to lock up your tool box and pick up a book.

Chris5k

Ok guys (dialed in) calm down, please focus on helping me and if you dont agree with other advice im getting then please just offer your advice to me because I value all the advice im getting, and I will consider it all, im tryin to take baby steps here because I got 100whp to try and gain on tuning lol... I dont want to take my car back to the dyno and blow another $75 to find out I picked up 20hp.. better than nothing but next time I go I want to see 300whp.. I think thats not asking too much out of my combo..

Been driving my car the last couple days and it feels like all the jerking in high gear is gone thanks to the correct plugs... I think the jetting is gonna get rid of the very little bucking it has in low gear when the engine is cold...
the timing seems to be very close, might try just a hair more but it might ping.. damn carb gaskets hurry up and get here!!

Chris5k

Sofa, I was going to cut the hooker y-pipe because If I remember correctly thats a 2.5" outlet... so instead of dual 2.5" into 2.5" with a 3" catback it would be dual 2.5" to 3" catback... but ill have to double check that it would be a hellava lot easier to just bolt up a catback..

Dialed_In

iTrader: (3)

Don't try to tune it cold, tune it when the engine is at operating temperature. It's going to run rough when it's cold, that's what the choke is for. Last problem I had was with the car running rich at part throttle on the street which caused it to buck. Chased it down to the PV opening too soon. May be something to look at. IIRC, you said it was running good at WOT so a jet change is going to affect that. If you go down on the primary jet, you're going to want to open up the PV restrictor to compensate. Not normally reccomended since that's not reversible.

Sounds like you're chasing a proper fuel curve. Only real way to get it right is by altering the emulsion orifices and PVCR using EGT and A/F monitors.

Chris5k

Dialed in, yeah I never tried to tune it cold, atleast not since I was younger and learned that the hard way... I probably wont alter anything in the carb that cant be reversed just for the pure fact that I paid $100 for the shortblock and honestly dont have alot of faith in it, it was rebuilt with what looks like advance auto parts products.. that said when I do build my own bottom end or buy one I believe to be reliable I will tune it more in depth..
not that this one has any major problems as of yet.. when it does im going for higher compression...
I still think my power valve is coming in too late.. just let me show you guys the dyno sheet before you prove me wrong.. not saying im right.. but just gimme a couple more days and I'll get it on here

Sonix

iTrader: (1)

Usually bucking is a lean mixture I thought.
Overly rich just makes it feel lazy.

If you're seeing lean on the dyno, then it's lean. Hard to argue that.
I must have missed the part in this thread where you know that you have a vacuum leak? I'd make that priority number one either way. Use starter fluid or propane to be sure it's gone.

I thought the reason the 'king of the chesterfields' was telling you to use the "advance timing until it pings" was because you had a factory pointer and aftermarket balancer, or some reason that made your pointer completely unreliable? Either way, i'd say getting your timing right is priority #2.

Then richen up the carb across the board. You'll probably find your timing needs change with a different fueling curve, so you have to go back and forth. I'd tune for max power, then worry about driveability (part throttle mixture, etc)

The amount of power you seem to be down will be VERY noticeable, go back to the dyno after doing a fair bit of tuning. One thing though, $75 is like 2-3 tanks of gas right? So don't waste too much fuel chasing a tune, if you can use a dyno to tune it cheaper

My big beef here is if your dyno operator watched you do a run showing 16:1 and 14:1 A/F, what did he say? "Huh, wanna try another pull now? think you should take off your air cleaner now?" I'm wondering why that $75 didn't come with some helpful advice, I mean they do that all day long, they could give you some suggestions, unless they're completely useless. Do you have another dyno to go to? I'd look for one that has some tuning experts working there (Which I would have hoped would be at any dyno...)

Chris5k

Sonix, im not sure that I have a vacuum leak, was just asking if vacuum can leak through the idle mixture screws because one or more (cant remember now) are leaking a small amount of fuel.. and no the dyno operator did nothing but get in my car and push the pedal, I asked him if I could take my air cleaner off, and he made no suggestions what so ever, and as i said before, I asked him if he saw any more potential in my engine and he said no, thats when I realized he couldnt careless what my car did. I really wish I would have played with the timing after the first run.. but with the wrong plugs and etc.. it probably wouldnt have been a big difference. the next closest dyno is a Mustang shop, and just like rev extreme they deal with 90% or more EFI.... and boosted applications, so when they see my turd they will probably be *******s too. I tried to have a dyno run there first and their opereator was too "sick" to do it, I bet if I pulled in with a twin turbo 5.0 he would have felt fine...
----------
I have an advance auto parts timing pointer and summit balancer... pretty sure I just put the wrong pointer on, but yeah the pointer was saying the timing was WAY off like 60 degrees... lol I'll look into that and try to find the right pointer

Chris5k

So I have a new question... If my valves were not adjusted properly could this make a noticeable difference? when I adjusted the valves the car was running headers and the y-pipe... so I couldnt hear anything, and although id like to say they are fine, there is a good chance they arent. I will readjust them before too long, just wondering how big of a difference this could make, even though I dont hear them constantly clattering or falling off the pushrod... car getting frustrating

F-Body Demon

iTrader: (1)

Depends on alot, like intake/headers/ignition and just what kind of heads are you running? Also what is the LSA and Duration on that cam?

I have a 400 sbc stock crank, hyper-u pistons CR of 10.9, 6" Capscrew rods. Lunati voodoo .525/.549 with a victor jr intake and AFR 195 Eliminators. She runs 530 Hp 548 Tq but everything you see here minus the AFRs made 425 hp 495 Tq with some 083 smoggers