TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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Well guys my buddy has a 89 LO3 with less that 100k on it. It is a very good running engine and it is amazingly smooth running. The only thing done to it is an open element. I just cannot understand why it is running a 16.7 @ 81 mph. We got the best time with 2 degrees on timing so far. Having owned an LO3 I know that they are quicker than this stock, but I had a five speed. Like I said it runs great with no hesitation and a great idle. We have fully tuned the car up and repalced all the sensors. Where else could I look into this?
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Could be lots of things, these cars had so much variability from the factory I wouldn't be too surprised to see a full weight stock L03 with tired suspension and a 2.73 open rear run a high 16 second 1/4 mile.
I would say the right combination of stock transmission, worn suspension bushings, stock exhaust etc could easily be the culprit.
Another calculator I found is saying 141hp at the flywheel and 130 at the wheels.
These cars were rated stock for 170hp at the flywheel... I dont know if losing 15-20 hp over the years is within the realm of possibility or not, but these are assuming a 3600 lb car (With driver) which I think is a fairly good ballpark estimate for the weight of that car unless it's absolutely gutted.
Another calculator I found is saying 141hp at the flywheel and 130 at the wheels.
These cars were rated stock for 170hp at the flywheel... I dont know if losing 15-20 hp over the years is within the realm of possibility or not, but these are assuming a 3600 lb car (With driver) which I think is a fairly good ballpark estimate for the weight of that car unless it's absolutely gutted.
Those calculators are waaaaay off, trust me. Your friends car has 100,000 miles on it with no real mods, thats a very regular e.t. for that car, hes right around 3600lbs, and 140-150rwhp.
sounds like your friend needs some practice. the specs on my car are just about the same as your friends except mine is a 91 bird. the only time i run that slow is when i dont catch traction and spin through first. you wouldnt think that would be a problem at the track but with an open differential and 215 street tires you'd be surprised.
I just cannot understand why it is running a 16.7 @ 81 mph....
His 60-foot would have been a very key factor, what was it....?
__________________ 1998 Trans Am: Mystic Blue w/Tan Leather, Automatic, T-Tops, Daily Driver.... 1990 Trans Am GTA: Black w/Black Leather, 5-Speed, T-Tops, Few Mods.... 1989 Trans Am TTA: White w/Tan Leather, Automatic, T-Tops, Garage Queen.... 1986 Chevy Camaro V6: Blue w/Black Cloth, Hardtop, 355-TPI Swap, 700R4, MS-II....
seems way too slow to me. My stock 5speed was a full second faster, the manual trans doesn't make THAT big of a difference. I would bet something is wrong with it, maybe running out of fuel up top, hard to realize sometimes. Check fuel pressure.
Right and like I said it is the best solid running third gen 305 I have been in, you would never think it would be this slow. If it was going to act like this you would think something in the way the car runs would be a red flag but it acts great.
another thing to consider if you havent already done it is the full seafoam treatment. you'll be amazed at all the gunk and carbon buildup that stuff will get out.
seems way too slow to me. My stock 5speed was a full second faster, the manual trans doesn't make THAT big of a difference. I would bet something is wrong with it, maybe running out of fuel up top, hard to realize sometimes. Check fuel pressure.
M5 cars have better gearing, in the transmission, and the rear, it can easily affect e.t. that much. In an m5 car there is more oppertunity to power shift, and come out of the hole much harder. The op could try a good tune up, plugs, plug wires, distributor maybe, oil change, and maybe make sure there is like a quarter tank or less, but you cant expect this car to run what an m5 will run. Imho I would be happy if it ran a 16.7 with in its current condition.
2.73s + 2.2 60' will most definitely equate to a high 16 second 1/4 mile run...
that doesnt guarantee a high 16 second e.t. here are two of my timeslips:
1.)
Dec 13 2007
Temp: 65*F
10:22pm
this was the first time i ever went to the track. i had the open element, 6* advanced timing and the 160 stat with the car at approx. 160-170 degrees and caught a dead hook off the line.
on this run all i had on the car was the 160 stat with the car running at 160-170 degrees and 6* advanced timing. no open element on this run. also caught a dead hook on this pass.
M5 cars have better gearing, in the transmission, and the rear, it can easily affect e.t. that much. In an m5 car there is more oppertunity to power shift, and come out of the hole much harder. The op could try a good tune up, plugs, plug wires, distributor maybe, oil change, and maybe make sure there is like a quarter tank or less, but you cant expect this car to run what an m5 will run. Imho I would be happy if it ran a 16.7 with in its current condition.
why would you be happy with that? its way slower then it should be. Read my post on my stock TBI car and what it ran.
Make not of the elevation(s)
In this Low revving, no cam TBI cars--I don't think autos and manuals are as far apart as you think. Certainly the gearing isn't a major difference
Manual cars can weigh up 120lbs lighter than autos, they usually have a very nice rear, 3.23, 3.42, a few 3.73s out there. Rear gearing alone can drop up to .5 off of an e.t. There are a few Lo3 auto cars that with low mileage, with a good tune, good traction, and fair weather that can go as low as a 15.9, however I dont consider that a common e.t. for these cars. Rated at a 16.6 from the factory, whats so hard to believe that one pulled a 16.7 with 100,000 miles on it, imho i dont think you can expect anymore out of the car, theres nothing wrong with it.
A very skilled driver can make an enormous difference in an m5 car at the track. Its not uncommon for an m5 lo3 to go low 15s, they weigh less, transfer a little more power, and have better gears.
Manual cars can weigh up 120lbs lighter than autos, they usually have a very nice rear, 3.23, 3.42, a few 3.73s out there. Rear gearing alone can drop up to .5 off of an e.t. There are a few Lo3 auto cars that with low mileage, with a good tune, good traction, and fair weather that can go as low as a 15.9, however I dont consider that a common e.t. for these cars. Rated at a 16.6 from the factory, whats so hard to believe that one pulled a 16.7 with 100,000 miles on it, imho i dont think you can expect anymore out of the car, theres nothing wrong with it.
that 120lbs is like .10.
Secondly your using examples of rear end gears that were not available in the LO3 5 speed. I am very sure they had 3.08s with nothing else optional.
Lets look at stock VS stock. Not a 5 speed car with 3.73s
Like everyone else is saying, it depends on the gears too.
I know my 89 RS 305 TBI, 5 speed, not sure yet but I think 3.08's (what dealer said). Wouldn't be suprized if it was 3.42's or something like that.
Ran a best I think 16.2 with the rear tires at 30PSI.
Keep in mind I think it will run somewhere around mid to low 15's, but the second gear syncro is pretty bad, and I had to slow down to get into second.
I also have a G80. This is a video of a launch I had against a Mustang. If you watch it going down the track you can see my car lose a lot of speed.
Secondly your using examples of rear end gears that were not available in the LO3 5 speed. I am very sure they had 3.08s with nothing else optional.
Lets look at stock VS stock. Not a 5 speed car with 3.73s
Where do you get 16.6 from??? Cite you source.
I've read 16.6 @83mph 1/4 mile, and 8.6 0-60 in many different articles, but since I cant find any now Road & track sports and gt cars special w/auto. 1990 I beleive,not for sure but its on a poster I have that says camaro tech in the middle and tells a little about each gen.170hp-20%=136rwhp+3500lbs, I dont think your going to get much more then a 16.7 out of that.
Last edited by camshaftxe; 05-10-2008 at 01:40 AM.
camshaftxe,
I think he can get into atleast he 15's or should.
My car ran a best 16.2 last week having to slow down to hit second because of the sycro's
seems way too slow to me. My stock 5speed was a full second faster, the manual trans doesn't make THAT big of a difference. I would bet something is wrong with it, maybe running out of fuel up top, hard to realize sometimes. Check fuel pressure.
the camaro/firebirds with manual trans had 3.08 gears so maybe thats why its that much faster
i went from 2.73 to 3.08's in my automatic car and went from a 15.4 to a 14.7. of course the difference will be different in every vehicle caus mine has been cammed and all..but that is quite a difference.
hmmm im pretty sure it is u can cut alot of time off your 1/4 with gears trust me also the actually gears in the tranny are different the autos were geared to suck lol 5 speeds are alright
hmmm im pretty sure it is u can cut alot of time off your 1/4 with gears trust me also the actually gears in the tranny are different the autos were geared to suck lol 5 speeds are alright
like i said i cu toff 7/10's of a second with a 3.08 swap.
