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Squidward · 12-20-2016, 03:23 AM

First time at the track with 3.73's. I got 2 passes in. The first was a horrible 2.6 60' as I smoked the tires and had to pedal to get traction. End result was a disappointing 14.6.

Next run I gave it a couple of tweaks. I turned timing back to 18/38 (my summer tune is 16/36), and did a tiny tweak to bring the secondaries in quicker. By launching carefully, I brought the 60' back to 2.1 (still

), and ran it to a best ever 14.1 at almost 96.

I tried to hot lap it for a 3rd pass before eliminations started, but temps started climbing as I went to the staging lanes. I turned it around and shut it down, and it was puking water everywhere from the water pump. I was done for the day, and had to fix the pump issue to drive it home.

So... I have two issues to address.
1. Crappy traction and 60' (still). I will get a set of rear wheels with sticky tires.
2. Power is flattening out just above 5k. I gotta figure out if this is just "the way it is", or if it's some sort of valve float or fuel issue. Back to the lab.

69FIREBIRD76MM · 12-20-2016, 03:28 PM

Get a set of 26"-10 slick or drag radials, I would suggest timing 34-36`, launch off idle for best 60' , may be a 650 hp holley will be a better choice, check fuel system see how much time it takes your pump to fill a gallon can, last valve springs probably need replace. Just my 2€'s.

Squidward · 12-20-2016, 04:22 PM

Quote:

Originally Posted by 69FIREBIRD76MM

Get a set of 26"-10 slick or drag radials, I would suggest timing 34-36`, launch off idle for best 60' , may be a 650 hp holley will be a better choice, check fuel system see how much time it takes your pump to fill a gallon can, last valve springs probably need replace. Just my 2€'s.

I found improvement going from 36 to 38. I launch off idle, right off the brake. Carb is a Quick Fuel 780 VS. Springs are Crower 68404's, with 3k miles max on them, probably less. Fuel pump is stock mechanical, and might be a weak link. I thought the big Holley fuel bowls might overcome a previously suspected delivery issue. As such, I can't do the "fill the can" check.

Would too much lifter preload put me in a valve float situation? I run about 3/4 turn past zero. Should I take it to 1/2 or maybe 1/4 turns preload?

Thanks for the suggestions. I am shopping for a pair of cheap 15x7 or 15x8 wheels with the right BS to put something sticky under it. I have been feeling the crunch over the last year of funding/working on 2 cars.

69FIREBIRD76MM · 05:51 PM

Have you done a compression test on the cylinders?
Buy some jegs star wheels or visions 15x8, 4.5 bs. Lighter than stockers.
The lifters preload should be fine.

Squidward · 06:25 AM

Quote:

Originally Posted by 69FIREBIRD76MM

Have you done a compression test on the cylinders?
Buy some jegs star wheels or visions 15x8, 4.5 bs. Lighter than stockers.
The lifters preload should be fine.

This week I should be ordering a pair of 15x8 Vision wheels.
https://www.summitracing.com/parts/vsw-55-5861

Then I will need to decide if I will do slicks or drag radials. I will drive to the track with the spare wheels in trunk/back seat, and then change from street tires to race tires. I am leaning toward slicks.

Should I do a 26 x 8.5, or a 28 x 9 Hoosier?

69FIREBIRD76MM · 12-23-2016, 08:55 AM

Quote:

Originally Posted by Squidward

This week I should be ordering a pair of 15x8 Vision wheels.
https://www.summitracing.com/parts/vsw-55-5861

Then I will need to decide if I will do slicks or drag radials. I will drive to the track with the spare wheels in trunk/back seat, and then change from street tires to race tires. I am leaning toward slicks.

Should I do a 26 x 8.5, or a 28 x 9 Hoosier?

If I were you I go with drag radials, I believe Hoosier makes, a 27" tall tire, those steel rims are cheap but heavy,
This will be my choice better.
http://m.ebay.com/itm/JEGS-Performan...257Ciid%253A20

Squidward · 12-30-2016, 06:56 AM

New electric fuel pump arrived yesterday, so hopefully this might address the nosing over. I've noticed my fuel pressure was running a little lower than before.
This pump will be a pusher pump for race only. It has a check valve so the stock mechanical pump can pull around it instead of through it when it is off (normal street use). Keeping fingers crossed.

I've identified the tires I plan on getting. MT ET Street Radials.
https://www.summitracing.com/parts/mtt-3754x

I read a Hot Rod test with these vs. MT bias ply slicks, and they didn't seem to lose much, if anything. And they had better high speed stability. I figure these should be a step up at my performance level.
http://www.hotrod.com/articles/2016-...good-et-drags/

Will keep this updated as I get back to the track.

Squidward · 02-19-2018, 06:29 PM

Best ever run yet, but still not where I want it to be.

Pontiac Heaven 2018. Changes since last year:

MT Pro Drag radials, 275/60/15 on 15x8 wheels.
Carter electric pusher pump in the rear feeding stock mechanical pump.

First attempt at a pass discovered a hose leak at the pusher pump that was spewing at the staging lanes. I was shut down, and pushed back. Quick fix in the pits.

1st run was a 14.233 @ 96.69. 2.165 60'. Timing was 36 total.

2nd run was best ever, 14.094 @ 96.89. 2.089 60'. Timing was 38 total.

The remaining 3 runs were lesser runs, due to 1) bye run in the trophy class, so I took it easy, 2) fudged up a 1-2 shift, hitting the limiter, and 3) degrading weather conditions that were slowing everybody down. Last run was 14.171 @ 96.46.

Power peak was around 5000-5200, and it started nosing over a little after that. It really didn't break up at the 2-3 shift like it had in the past. Runs were pretty clean, so the car was doing its part.

13's are eluding me. I didn't spin on launch, but I am not much better than I was when footbraking on hard 235/60/15 street tires. I tried loading up the converter to 1500-2k rpm, but really didn't see a big diff. Maybe this is all the little motor can do?

This car will get fuel injection, and then I am done. At that point, it will get what it gets, and I am not going any further with track upgrades. It has been a fun adventure so far.

wheelspin · 02:35 AM

Hey Sean,
Nice job of tuning your combo from 16+ seconds to 14 flat in the high 90s

. Taking 2 1/2 seconds out of any vehicle is a sizable achievement especially when it involves a heavy car powered by a "small block" Pontiac

. Consider adding a higher stall converter to help the smaller inch motor to more quickly get into and stay in it's working range.

My current ride, a '65 Buick Sport Wagon greatly benefited from a tight 13"2400 rpm stall verter to better launch it's 3800# mass and keep it's 340" Buick motor in the happy range.

Squidward · 02-25-2018, 05:11 AM

Thanks, Les. I was hoping you would be able to take a trip east this year to the PH event. I would have enjoyed saying hi.

Fuel injection is arriving in a day or two. We'll see how that changes things. My carb seems to perform awesome on the street, but IDK... maybe it's not cutting the mustard on WOT. I really needed to tune the WOT. My friend Mike always tells me to stop at the end of the track and pull a plug, but I never do - I get caught up in the moment. I have a bung to weld in for an O2 sensor, and was going to try it that way. But EFI will do the math for me now.

I had no spin on launch, but my 60 was still disappointing. I rationalized the same thing: converter could stand to have a little more nutz. 2000 stall was an improvement over stock converter, but it probably needs more to get to a sweeter spot in the power band. I'm not sure I will change the converter, tho. I don't race enough such that I would want to sacrifice street driving too much. I already have regrets that the 3.73's don't let me do any real highway driving.

I've been considering a 4L80e, which would require a new converter anyways. Then I would have 3 gears for the track, and one for the open road.

For now I will scratch my head a little. On paper I thought I had a good build. 40 over 350, ported #12's, 219/227 Lunati cam, QF carb, HEI triggering an MSD6AL, Carter electric pusher pump feeding a stock fuel pump, 3.73 rear gears, 275-60-15 MT Pro Drag Radials, TH350.

wheelspin · 02:26 PM

On slicks (DOT or full slicks): ideally, you want to run the narrowest width and lightest slick possible that produces minimal wheel-spin on launch. Dead hooking your 350 powered Bird is not desirable since it will the motor's momentum. The 275 MTs are heavy flywheels that must be accelerated from a dead stop. Son Mike's '66 500+hp GTO runs 1.7 60fts., 11.6, 117mph on M/T 235/60 X 15 (8.3" wide) ET Street S/S DOT slicks.

Trans/converter: your 350 trans is ideal for your street/strip use, IMO. The 4L80E and the turbo 400 trans are heavier and have more parasitical power losses than the 350. The key to a proper converter for your use is the term "tight" meaning built with far less slippage throughout the operating range and less heat is generated as a result. A tight converter on the street feels more like a clutch with limited take-up. The only automatic o/drive trans that I would consider for your use are the GM 700R4 and 2004R series units that would easily handle the 350's torque without adding a lot of $$ hard parts.

I believe you have a well sorted 350 based engine package and that traction is probably the least of your problems. As someone smart once said "build a BIG motor & turn it slow OR build a small motor and twist it tight". The key is to keep your engine in it's working range.

Lee · 02-26-2018, 04:40 PM

Quote:

Originally Posted by johnta1

Higher stall converter.

Yes, along with a posi.

Story of my 326 '67 Firebird:

I bought the car from somebody who had ZERO idea what had been done to it. It was a 326, and it had a larger than stock cam - which made the low-end even worse. It did have a posi, a 3.2-3.3'ish gear ratio. Dual exhaust with a set of Hedman headers.

I took it to the track and it ran high 16's, with painfully slow 60' times. No spin, didn't even need a burnout. On the last pass I decided to try something - I went through the water box, but did NOT do a burn out. I started doing a burnout at the line as the lights came down, and let off the brake with the engine at a much higher rpm, spun a ways, hooked and bogged, but still ran a half-second faster than the previous "best" run. (track crew wasn't happy with me!)

I ordered a Hughes 3000 torque converter. Behind the low-TQ 326, the actual stall speed was closer to 2800, but still WAY better than the stock converter. The engine would now jump up into its powerband, and would spin the tires for the first time. Back at the track, I actually had to do a burnout! NO OTHER CHANGES, e.t. dropped to 14.9's.

OCMDGTO · 02-27-2018, 11:05 AM

X2 knocking 2+ seconds off a combo without adding cubic inches is quite an achievement!

68azbird · 03-02-2018, 06:36 PM

Saw a stock eliminator 68 firebird run a 11.19 @119 mph today with a pontiac 350 FWIW

Lee · 03-02-2018, 07:38 PM

Reading your thread in more detail...

Have you tried shifting earlier? Tachs are not always accurate, some read high and other can read low. I went from 13.8's shifting at 5000 in one car, to running 13.2's shifting at 4600 (as indicated on the tach). The tach on my current T/A clone reads high - the error grows as the RPM increase, too. I do not hold the tach reading anything other than a reference - I try different shift points until I find where the car runs best.

Did you try different squirters in the carb? You mention you have no spin. Small motor and a mild converter, so you may be as good as you are going to get. But squirters a few sizes bigger might have helped you off the line. A tenth gained on 60' can be over 2-tenths at the finish line. Hopefully your EFI system will have adjustable enrichment controls, which will do the same thing as changing squirters.

I still think you need more converter, but I'm sure you'll remedy that if you go with the 4L.

Squidward · 10-27-2018, 06:47 PM

Update from last night:

Best run of 3 last night: 14.847 @ 91.37. 2.328 60'. It goes without saying that last night was a bucket full of anger and disappointment.

I made my first run with timing at 36 degrees (summer driving tune), and netted a 14.951 @ 92.28.

I then waited 2 hours due to some douche oiling down the ENTIRE track in a blown pickup. For my 2nd run I bumped timing to 38, and fattened up WOT AFR to 12.2 from 12.6, and got the 14.847 @ 91.37 with a slightly better 60'.

3rd run with no changes, shortly before they shut things down, was 14.923 @ 92.39. 60' was an appalling 2.510.

Last night's session was a "go light" session. I didn't feel like packing up all of the drag radials and other stuff, because the Friday Night Drags are always a $#** show of Mustangs, Challengers, Camaros, Chargers, and Hondas. But a credit to the late model guys: There might be a million of you, but at least you don't shut down the track for an hour and a half by hosing down an entire 1/4 mile.

I've never had to feather the launch like last night, even on hard street radials (235-60-15 Coopers, @ 22psi). I suspect the track prep was minimal, so maybe that was a contributor. So while the spin on launch was not desired, it seemed to have great power on launch and through 1st gear. 2nd gear was ok, and seemed to nose over/flatten out at 5000-5200, and 3rd gear seemed somewhat lazy through the end of the quarter.

I LOVE the FiTech. It is awesome for street driving. But I simply do not have it figured out for the track, as evidenced by my MPH. I was down a good 5+ MPH from my previous outing last February.

Pontiac Heaven is coming up in a few weeks. We'll see if I can do better. I know I can get some runs in there, which will help with some tuning data collection. The track prep is usually pretty good. Drag radials will be used for sure. Right now I hope to get BACK to the performance I had with my Quick Fuel carb!