Anyone wanna take guesses at why it runs such terrible times? For those of you who dont know, they have been trying to make an LG4 car run some good times. With a rebuilt 305, they got 15.21 out of it.

Now they have a motor that dynoed 386 horsepower without a cat on, and they are running 14.78@90.75 mph and 13.10@108.95 on the bottle.

My guess is their stock quadrajet on a 386 horsepower motor is holding it back a bit. Also, is it just me or does the n/a mph look really really lame. 386 at the flywheel and they get a 90 mph trap speed??? Guessing that their car weighs 3600 lbs with driver, that puts them at 205'ish horsepower at the wheels....

 

wow that kinda sux

 

396 at the flywheel means nothing after you consider drivetrain losses.

Dyno results are also corrected to sea level so it's only a theoretical number used for comparisons. Racing at altitude will automatically reduce the amount of HP an engine can make. Where did they make the 1/4 mile pass? Bad weather conditions will also reduce the amount of HP and engine can make.

Yes, to run that ET and MPH they would only be making about 205 HP at the rear wheels in a 3500 pound car with driver.

 

They also mentioned that they used a different set of headers in the car vs the dyno.

I think the biggest problems they are having is the stock carb, and the stock distributor (non mechanical / vacuum advance). They have no control over the timing, which I'm sure is throwing a wrench in the works.

Im also sure there are some small tuning issues that need to be resolved that just come from patience and passesdown the track.

Bagz

 

I wouldn't be so quick to blame the stock sized q-jet. Those carbs can and regularly do put up much better times than that on well sorted Stock class cars. More likely much of the lost et is bottled up in the conv, chassis, suspension and rear gear areas. And that tank-like weight isn't helping them any either.

 

Yeah I was surprised being they hit really really low 13's with that LG4 and a 150 shot. And they did that head and cam swap on the LG4 and went really mild. The H/C swap put them at about where the L69's run off the show room, they could've probably hit at least mid 14's with the H/C swap and still been mild. Oh well, I still think those are pretty impressive times for an LG4, and had they gone with a little more cam, might've been able to reach 12's with the LG4 and juice.

But I think once they get the tuning issues out of this new engine, they'll get it into the 13's. Q-Jet's can be tuned to run just about as well as any carb out there, I was just never able to find anyone around here that wanted to work on one.

 

3.73's, posi and slicks isnt an aweful setup. And suspension stuff I dont think is costing them 15 mph n/a. I am wondering if they dynoed that motor with a different distributor and carb... Does anybody remember if they said anything about that?

 

The swap they did with the headers is enough to kill top end hp. Also, the 3.73's might not be an awful choice unless the motor really wants a bunch more gear for the tire they're using. But the easiest thing they could do is shed about 300 lbs from it.
Putting the headers they dyno'd with, shed a bunch of weight and 4.10's with a 26" tire would likely make for a big improvement in et's.
One thing to keep in mind, the top end hp number becomes irrelevent if the combo never allows the motor to get to that area of the curve. That is one reason why two similar cars with equal motors are different on the track even though they should run the same. It takes the complete package being right to get the most out of it.

 

The potential for the CCC Q-jet is there - I ran low 13s with one on a 408 with smog heads. Everyone said the carb was holding me back. I finally gave in - mainly for the timing control. $450 later - Tricked out Holley 750 and MSD dizzy and three days of tuning the car picked up .08 seconds. That was due to the ignition curve that I had better control over, not the carb - needless to say, I was expecting a little more from the timing swap,,, but that's how it goes sometimes. Anyway, the CCC Q-jets are a little tricky, but they can deliver.

I've also "tuned" basically stock 350TPIs to run mid 13s with ported cast iron manifolds with the stock mufflers and cat back,, minus the cat. So unless the converter is killing the car, I doubt it's exhaust related.

I think they just have the thing way out of tune. They have the timing too low - 0 degrees, it should be up around 10 - 12 with the stock LG4 chip. They need to adjust the lean and rich stops, if that doesn't get it they'll need to change the primary metering - a chip does nothing for WOT fueling - full rich is full rich. Drilling the brass inserts and installing jets for the secondaries helps in tuning. Putting on a taller air filter and running a 11" lid, so you have an open element will help if they haven't removed the charcoal ring that sits right inside the filter. They just need to get someone on that thing that knows a little about tuning the CCC system.

 

I'll give you my take on that car - I am actually gonna write to the magazine about the car's lack of performance.

First of all 15.2 is not too bad for a 305 in a car like that, regardless of whether it was rebuilt or not. But 14.8 is merely a tuning step for a 305, not a 380hp+ 350. 380+ hp should be trapping at 110+ in a 3500lb car, so its 20mph off! ouch.

What they need to do:
Buy an Edelbrock Micro-Plus timing computer off e-bay or used elesewhere and re-install all computer controlled hardware (distributor & carb)
Good headers and 3-1/2" exhaust
Tune the damn carb with an A?F gauge
TQ converter 2200-2800rpm
3.42 or 3.73 gears
Mild roller cam (like a 210/220 cam)

I still think the combo is mis-matched, but it should be able to crack mid 13's even with that going against it.

 

They used headers on the dyno that didn't have the heat riser valve, and a 3" muffler on the end of the y-pipe instead of a cat. The carb and distributor on the dyno were non-CC. The aircleaner on the dyno was a big tapered stack.

The best time they did achieve in the car was after a chip change. They never gave the 305 the benefit of that little favor.

The strip was at 3000' elevation, and all the times they published were corrected for elevation to sea level (they never published raw numbers).

They should be embarassed (and they seem to be). Still have a stock stall converter, for instance . And, I agree, they probably have a big-time but simple tuning issue.

My combo with a tranny that shifts 2-3, 3.73 gears, and slicks at sea level would shame all their NA times. My times thus far are totally "untweaked".