http://forums.performanceyears.com/g...s/icon_mad.gif Car was running 10.20's. Replaced aggresive solid flat tappet cam with aggresive solid roller...No gains...Improved D-port heads throughout lift range with over 20cfm gain at higher lifts...No gains...Replaced 1 3/4 headers and non-mandrel bent 'X' pipe system with 1 7/8 headers and straight 3" pipe...No gains... Can change jet sizes 10 numbers with no change in ET. Converter slippage under 6%. Traction and 60fts great. Is it possible that a Victor intake for 4500 carb is restrictive on a set of 280cfm D-ports?? THe plenum has a little work, but runners are as cast. Don't know where else to look http://forums.performanceyears.com/g...n_confused.gif

Fuel supply maxed out?
Air intake restrictive?

PHILLYGOAT

I run a Mallory 140 from a cell in trunk through #10 line with high flow Holley regulator. I have also added a Mallory 110 and have made back to back runs on both pumps and with only the 140. No difference in Et or MPH.
I run a Dude scoop and no air cleaner at track. Have lots of clearance above carb. Have tried running the car with no hood and two 3" air filters stacked on the Dominator. No difference. The intake is the only thing I have not changed. Would expect the Victor to be border line too much intake for this combo, not restrictive!!

TJ, cam specs? Intake centerline as ground and installed at? My D-port motor did not like the Warrior Dominator as much as the HSD with HP 950. Solid roller at 2 degrees advanced in at 102 ICL. 109 lsa

Sounds like you're maxed out on head flow.

i agree that there may not be much more to gain with the heads u have dave.

u mite try a bigger fuel pump tho, if u could borrow one from someone. there may be some power there.

torqjunki

If the car is not responsive to tuning changes, then I don't think the problem is with cylinder head or manifold flow. Changing the jets 10 sizes should make a change in ET (up or down) even if the heads/manifold are in choked flow. This point would seem to indicate a fuel delivery or gross fuel mixture problem. You have already answered the question regarding adequate clearance above the carb.

Keep looking. Have you done a fuel flow check (how many seconds does it take to pump 1 gal of gas)? If it takes more than 15-20 seconds to pump 1 gal, find out why. Kinks in the fuel line, dirty fuel filter, fuel tank/cell is adequately vented, etc.....I had a similar situation and found the pump was going bad.

Is there any way you could install an A/F monitor to see where you are at? Some other simple things to check would be the metering block gaskets and the integrity of the PV if you run one, and make sure that the boosters are not loose. Metering block gaskets can cause all kinds of tuning havoc if they leak across circuits or if you inadvertanly use the wrong one (2 vs 3 circuit 4500 or heaven forbid a 4150 gasket).

When you changed cams, did you change valve springs? How much seat pressure and open pressure are u running? Do the valves stay lashed???

Runs the same if the jets are up or down 10 sizes? Is the carb getting to full throttle?

Sounds to me like the DRIVER is upshifting way too red, uhm late.

Did you try upshifting at circa 5000RPM?
...and work the converter in 3rd gear.

Only other variable is Total Advance: What has been your spread of Total ADVances in all your efforts?

Cam is Comp 276/284 @.050 ground on 108, installed at 102. Carb is definatly getting wide open. I have a EGT installed. It crosses the line around 1350. I intalled different boosters with small umbrella for stronger signal and it went to 1100. Jetting down brought EGT's back up, but did not run any better once jetted properly. I have not tried pumping gas in a jug recently, but did it when I set up the fuel system. I will do it again. Valve springs are new and set up by competent machine shop. They are H-11 tool steel. Timing has been tested between 30 and 36. Dist is locked out. Runs best between 30 and 34. Gonna try another carb. I recently did some chassis dyno pulls and my AF showed 10.2 I took 11 jet sizes out and got 10.4 I did not believe these numbers at the time because the car was running well and not responding to jetting down. Maybe the info was correct.

Did your EGT change when you changed jets?

Very little

Dave....are you running two regulators?....one for each bowl?

Dave, my old RAIV 40 was that way(although at alot slower times) because I had a major reversion problem with it until I got a smaller diameter header. You have a pretty small size for your HP already. Anotherthing that improved it was more duration on the intake than exhaust. That can compensate for a defecient intake port.You can try more rocker ratio on just the intakes to try that direction without a cam change.
Do you have an X pipe on it? I was impressed with the performance with adding that to my system. It runs as fast with the X,mufflers and tailpipes as it did with th4 less weight of no system and open headers.



You just need to get those Wentzlers better I saw at G&G!

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by torqjunki:
Very little </div></BLOCKQUOTE>

If you are not seeing a performance or EGT change with that big of a jet change, you are getting close to where your problem is. Did you notice this problem before or after you changed boosters??? Was anything else changed with the booster change (e.g. air bleeds)? Have you tried using the original boosters to see if it makes any difference?

Testing with another carb might help isolate the problem.

Some other thoughts, double check to make sure the air bleeds are not plugged up. Double check the float level and if your floats are brass, check to see that they don't have a leak. Based on your A/F numbers being rich (and unresponsive) brings me back to verifying that the carb has the correct metering block gaskets for your dominator.

OK guys, what else could make the carb run rich and result in little change in A/F with a jet change 11 steps leaner? Bad gas or ????

Carb too small maybe???

There is no reversion on these 62's. THey flow 280cfm at .600 and .700 with out any tumble. I am afraid when I install the Wenzlers, it will slow down or run the same!! Something is not right with the car now and I need to find the problem before I change something so drastic. The Wenzlers I have must have been a bad experiment and should have been melted down for scrap. Not saying I can't fix them, but I should not have to. I will post the numbers Wenzler supplied with the heads to the previous owner and the numbers supplied by G&G.
Wenzler G&G

200 155 150
300 218 170
400 263 207
500 282 239
600 296 266
700 302 280

These are at 28" on the intake. He said the short turn is totaly screwed. I have epoxied one short turn and should get flow numbers later today or tomorrow. Regardless of which heads end up on the motor, I am going to have the head flowed with the Victor installed and will go back to a chassis dyno with wide band o2 to nail down the tune up before hitting the track.

When I had installed the boosters with the umbrella, it was very rich and I had to take a ton of jet out. I had a head gasket problem and had to shut it down before I got to where the car fell off. It did level off at some point and did not seem to respond much after that point, but I was trying to make the car pop or lay over or something to be sure I was lean. It never did. Unfortunatly, the head gasket was letting water in the cylinder that I was reading EGT off of, so that was not accurate. The final numbers showed the boosters slowed the car down and after the head gasket was replaced, I put the carb back to original and it ran 10.20's again. The car does not lay over at high rpm or miss at all.

running it on the chassis dyno may be a little misleading because of the G force of the car moving down the track, if the fuel system is not up to snuff......

Just another thought, but, isn't -10 fuel line a bit large? Could the fuel be stalling in the line due to G force?
But then again, that wouldn't be a factor on the dyno, huh?