Another Try....

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Bruce69Camaro
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Another Try....

#1 Post by Bruce69Camaro » Thu Aug 28, 2014 8:10 am

So this season started out with, as many of you know, a big surprise to me and my health. We things are finally getting back to normal and I'm planning to take the car back out.
Last year, was a big disappointment. I was told that my car should run at least high 10's, if the chassis was setup right, well I wasn't even close, so after some changes, hopefully my times will get better.
The car weighed with me, #3275, this year I'm looking at #3225, changed front springs from a tight Moog 6308, #380 to Moog 6314, #289, set the rear shock setting from medium to soft, added header extensions and taller front tires.
Ray did some talking to a cam guru and we changed the valve setting and set the timing back to 38. Maybe Ray will chime in and give a little details on why this happened.
One of the big things that was changed was my shift point. Last year, for some reason, I was advised to shift at 6000 rpm's by the engine builder. Many asked me why I was shifting so low with a cam that is good to 7300 and I couldn't give them an answer to the builders suggestion. So we raised the shift point to 6800, hoping that by the time I react, it will be more closer to 7000.
We also changed gears from 4.57 to 4.86.
Ray, am I forgetting anything?
My best time last year was 12.01 and my best speed was 113mph.
From calculations, my motor is somewhere in the 475hp range.
I'm hoping for mid 11's.
Once we proven out that our changes made a difference, I have a NOS system to try out. Right now, the jest are 57 NOS/ 47 fuel and with this small amount, I'm hoping to make it into the 10's, and if not, we will bump it up a little more until we get there.
Anyone want to give a guess on what it may run this year, with and without the bottle?
Those who think they know it all have no way of finding out they don't......... :scratch:

bracketchev1221
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Re: Another Try....

#2 Post by bracketchev1221 » Thu Aug 28, 2014 8:57 am

Basically, the short story behind all the changes was the front end was very stiff and being a powerglide car, I wanted to speed up the weight transfer. So the front springs were softened and the rear shocks were set soft to make sure the car will hook the first time out. After that the rear shocks will be stiffened until the car slows down. To increase low end torque, header extensions were added and a 4 hole carb spacer was added that was then removed for the nitrous plate.
The valve lash was changed by loosening the intake .002 and tighening the exhaust by .008 to aid in the exhaust flow from the closed chamber head with the small valve. This was basically to give it more time open to compensate for the small valve. The timing was bumped up to see if it responded due to the squarish dome of the closed chamber piston and poor flame travel. Also the fuel is changed from the 112 blue to the 110 octane purple for quicker burning to help this as well since the engine is a 12:1 motor. The shift point was a sticking point with me. I have never had a 3.76 stroke motor peak below 6800, so the shift point is going up. We will try 7000 to see if it keeps gaining too.
Finally the gears were too high at 4.57. Ultimately on motor, I could have gone to a 5.14 or so, but being on nitrous at 135 mph, that would put the rpm too high. So we settled on a 4.86 that should put rpm at 7000-7200 factoring conveter slip at 135 mph.

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Mike Peters
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Re: Another Try....

#3 Post by Mike Peters » Thu Aug 28, 2014 10:22 am

Keep a close eye on things if you intend on spraying it with 110 octane. Even the small jets in the plate can increase the cylinder pressure greatly.
"If winning was easy, losers would be doing it"

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Bruce69Camaro
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Re: Another Try....

#4 Post by Bruce69Camaro » Thu Aug 28, 2014 10:50 am

The track has Sunoco 112.
I was going to run the 110 on just motor, which the track doesn't have.
Sound better?
Like I mentioned previously, we're going to see how much of an improvement we made with just the changes we listed above and then I plan to run the NOS on a different day.
Those who think they know it all have no way of finding out they don't......... :scratch:

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1320quick
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Re: Another Try....

#5 Post by 1320quick » Thu Aug 28, 2014 11:29 pm

Good luck! It looks like a cool car. Hope you are able to meet your goals. What kind of nitrous plate? The bottle should wake it up for sure. 8-)
Ron
71 Nova - 3300lbs, stock suspended on a 275
5.35 132MPH in the thin Colorado air

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Bruce69Camaro
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Re: Another Try....

#6 Post by Bruce69Camaro » Fri Aug 29, 2014 4:55 am

It's just a simple NOS kit with a spray bar, good to 300, nothing fancy.

I'm hoping we don't need to go anymore than 150 to get me to my goal because the motor does have one weak spot that would keep me from much more past that, stock rods w/ 3/8" ARP bolts. I was told they we a heavy duty, dimple rod, but I guess I should have known better and stepped up to a 7/16" rod.
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wikd69
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Re: Another Try....

#7 Post by wikd69 » Fri Aug 29, 2014 11:47 pm

How long have your springs been in the motor ? I learned the hard way that they can lose tension pretty quick - I ended up bending some intake valves by peaking rpm a bit too high with tired springs. They do make spring testers you can use with the engine in the car.

Dunno how high you're looking to wind that orange beast but it's something to think about :thumb: :smt003
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
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BracketNova
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Re: Another Try....

#8 Post by BracketNova » Sat Aug 30, 2014 11:42 pm

What's your time slip look like? 60ft? 660ft? I would think you would be a lot closer to 11.0s than 12 something.


If you could, send me a PM and catch me up...I haven't been around much the last few years :/
"I always compare drag racing to lighting $100 bills on fire, only it's more expensive." - Craig W.

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'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
1.4257 60'
1700' DA

13:1 439 BBC
3330 lbs

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Bruce69Camaro
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Re: Another Try....

#9 Post by Bruce69Camaro » Tue Sep 02, 2014 5:57 am

wikd69 wrote:How long have your springs been in the motor ? I learned the hard way that they can lose tension pretty quick - I ended up bending some intake valves by peaking rpm a bit too high with tired springs. They do make spring testers you can use with the engine in the car.

Dunno how high you're looking to wind that orange beast but it's something to think about :thumb: :smt003
Springs aren't that old. I put new ones in when I switch over to a roller cam.

Only looking to rev it up to 6800-7000.
Those who think they know it all have no way of finding out they don't......... :scratch:

bracketchev1221
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Re: Another Try....

#10 Post by bracketchev1221 » Tue Sep 02, 2014 7:14 am

Ultimately 72-7300 should be high enough for this motor. The springs were supposed to be 200 on the seat and 550 open pressure. Its a little lower than I would normally use, but the valve is small. Its a 2.06/1.72 valve with a 3/8" stem. So I think it should be ok.

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BracketNova
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Re: Another Try....

#11 Post by BracketNova » Tue Sep 02, 2014 11:28 pm

I will share my wisdom...wisdom being everything I have learned the hard way. Our cars are pretty close to each other. I have a .060 over GM iron-headed (781s) 427, best time in sig.


You said your 60ft was 1.70...
Jet Extensions: Gotta' have 'em, assuming you are running a Holley. My car would pin the gas to the back of the bowl off the line. It would go then stumble and work its way out of it. Also, the extensions only go on the back - that's wisdom from a friend.

Slicks: What shape are they in? I let mine get below 40° during the off season. That's a no no. Got new ones on the car thanks to that life lesson. When they get colder than 40° they secrete all their awesome goo.

Suspension: Check for binds front and back. Binds will make your shocks far less effective. On my leaf spring car, I pull the shocks and Cal-Tracs and bounce the rear. It should bounce three or four times, and you shouldn't hear anything metal on metal etc. I found some issues with mine this summer.

Converter: Is it matched to your setup? I sent all my info to a converter shop and they sent me back what worked for my combo. I believe I flash at 4800 RPM.

Pinion Angle: Make sure it is right for your application. Fourlinks I believe are 0-1°, ladders and Cal-Tracs around 2°, and springs with slapper bars 4°. If that's wrong someone correct me.

Track: What's the track like where you race?


Down the track...
Carb: With it idling, take a peek down the barrels. One time I had the transition slot too far open on the secondaries and it was dribbling fuel out of the boosters at idle and flooding the car.

Carb Size: I'm rocking an 800 with a milled choke horn. You don't need a 1050 dominator, nor a 600. With nitrous is another story.

Jet Size: Whatcha' got? I'm hoping somewhere in the mid to upper 80's. 93's work good on mine with my e85 setup. e85 needs about 10% more volume over gas.

Fuel Pressure: I aim for 7 PSI. Too much and you over power the needle and seat.

Fuel Line Size: I believe they say a 1/2" or -8AN will support a high tens car. This will soon be the Achilles heel of my ride as I only have a 1/2" return style system. There's a fuel can test you can do as a baseline.

Shift: I run a Powerglide, I shifted at 6800 last time because I didn't have any 7k chips. Now I have said chips so we'll see this weekend.

Timing: My baby big block hates anything under 38°. Now that I won't have a traction problem this weekend, I can actually start to tune the engine.

Compression: What PSI do you get when you do a test? I'm at 220 I believe.


Answer as much as you can - we'll go from there.

- Greg
"I always compare drag racing to lighting $100 bills on fire, only it's more expensive." - Craig W.

Check out my website...
http://www.findmoneyraces.com


'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
1.4257 60'
1700' DA

13:1 439 BBC
3330 lbs

bracketchev1221
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Re: Another Try....

#12 Post by bracketchev1221 » Wed Sep 03, 2014 8:21 am

I'll try to answer as much as I can from what I have seen on the car. And why I left it as is. The carburetor first is a pro systems carb. It is rated in the high 840 range, so knowing Patrick's carburetors, it has jet extensions with the notched float, and generally the jetting is pretty close. The plugs were looked at the last time out, and they were considered to be a little on the fat side. So being that the car was not really run hard and that I wanted to drop the octane of the fuel from 112 to 110 for quicker burning I decided to leave the jets as they are until the car is tried again. The slicks are old, but the sidewalls don't really show any signs of cracking and right now traction was not an issue to get the car moving. For the suspension, the front end has been loosened up with spring rate, and the back of the car was raised to make the ladder bar closer to parallel to the ground. The converter is supposed to be a 5-5500, converter. I think it is a little tight for the powerglide, but it remains to be seen when the nitrous is put on. It may act better then. I did not check the pinion angle.

The track, well the track is not the best, but right now it is not contributing to any issue getting down the track other than higher elevation by about 700 ft above sea level. Fuel pressure is right around 7, but we'll see what it is at higher rpm. Same goes for the fuel line, it is a #6 line from the tank to the carb. The car hasn't been run hard enough to create any issues yet. I would like to have a #8 fuel line but that will come later. The car is a powerglide as well, and I am working on a 7000 shift point. That should wake the car up a great deal over short shifting at 6000. And finally the timing, it was at 36, but I bumped it to 38. The timing is locked out so I did not want to go too far and have starting issues. But next is 40.

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BracketNova
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Re: Another Try....

#13 Post by BracketNova » Wed Sep 03, 2014 8:46 pm

If he's got a fuel gauge that he can see while going down the track it would be interesting to see if the pressure drops off with that -6 line.
"I always compare drag racing to lighting $100 bills on fire, only it's more expensive." - Craig W.

Check out my website...
http://www.findmoneyraces.com


'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
1.4257 60'
1700' DA

13:1 439 BBC
3330 lbs

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Hitchcock
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Re: Another Try....

#14 Post by Hitchcock » Wed Sep 03, 2014 9:12 pm

Easy way to test you slicks sidewalls. Give your thumb a good lick, and rub it on your side wall. If you then see little micro cracks or little tiny Spider webs, the sidewall is shot.
73 Vette, moly back half
Pump gas 496
Two Pro Systems 950's
Chance 6000 converter

bracketchev1221
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Re: Another Try....

#15 Post by bracketchev1221 » Thu Sep 04, 2014 5:31 am

BracketNova wrote:If he's got a fuel gauge that he can see while going down the track it would be interesting to see if the pressure drops off with that -6 line.
I think on motor right now it will be fine. If it was to get into the 10's on motor I think it would push the limit of the 3/8" line.

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