finally got to race! need tuning seggestions

[redhead69]

Happy now.. got the mini spool in and she went straight today. First time Ive got to stay on it the whole track. I was happy with the way it launched but felt like it ran out of steam on the top end.. tell me what yall think heres was my best pass this morning

r/t .047
60' 1.939
330 5.712
1/8 8.976
mph 74.05
1000 11.888
1/4 14.384@89.49 mph

running a basically stock 406sb/th400 2500stall and 3.73 gears.. dot 28x10 slicks and hooked good. Doesnt my 1/4 mph seem slow for what I was running at the 1/8th??
Anyway I had a great day of racing and hope you all did too!! thanks for any input

eric

[bigjimzlll]

They have some good calculators on this site http://www.wallaceracing.com/Calculators.htm
sounds like it's running out of fuel on top...What RPMS are you crossing the stripe at?

[wild one]

Should be around 4000 - 4100 RPM at 89.49 mph with 3.73's ( here's the calculator that I used http://www.csgnetwork.com/multirpmcalc.html ). Your description says "basically stock 406sb" , so it's safe to say that your running a rebuilt .030 over sbc 400. What cam are you running - I only ask since I assume that when the engine was rebuilt you swapped out the camshaft. I know that when I ran my truck at the track it ran out of steam due to the stock cam profile ( I run a stock 1975 vintage 400 sbc/th350 combo that came from an impala station wagon ). The last 100 or so feet of track my truck stopped accelerating .

By the way, you ran almost two seconds faster than my best pass ( your 14.38 vs. my 16.15 ) but our mph were almost identical - your 89.49 vs my 90.5mph - how weird is that!

[redhead69]

cool thanks..there is a bunch of stuff there to keep me thinking

I was crossing just over 4k. Maybe I should have dropped the tailgate? lol.. hmm
It honestly felt like A) not enough fuel or air B) After shifting into third a parachute opened

[redhead69]

Wild one- Its got a crane blueprint cam 222/222 i think they call it the 375 horse 327 cam. supposed to be good at 1500-6500 rpm. The intake is a Dart Kool Can.. kind of a rpm airgap looking thing and my carb (which has got me thinking) is a 770 holley street avenger and if memory serves me its an off road carb. Also along those line of thinking it pulls hard through 5k in the first 2 gears why not in 3rd? I think I have the bug.. always wanting to go faster.. more more

[wild one]

Sounds like a fuel delivery issue, possibly not enough volume from your existing fuel supply system. What type/size fuel pump are you running, what size fuel line does your truck have and where is your fuel filter located? Is your fuel tank in the cab or under the bed?

[redhead69]

stock pump. Ive got an inline universal style metal filter under the cab where my fuel line switches from the -8(1/2") braided to a 3/8 hard line. Ive heard stock pumps are good for 400hp.. I will have to test mine and make sure its up to snuff

[wild one]

O.K. - first thing to do is move the metal filter from before the fuel pump to after the fuel pump. By putting the filter before the pump, it can create turbulence in the fuel stream effectively aerating it. This causes the pump to lose its ability to "pull" fuel from the tank which will lead to an empty carb float bowl.

The factory style pumps i.e. mechanical pumps are meant to pull fuel from the fuel tank unrestricted (only the fuel pick-up sock should be before the pump). Once the fuel has gone through the pump it is pressurized and will flow without any turbulence through the fuel filter. After you have moved the fuel filter, re-run your truck - this by itself should do the trick. If the truck still falls on its face in third then check the fuel pressure and if possible the amount of volume the pump is suppling. You might also consider extending the 1/2" fuel line to the fuel pump to help the pump "pull" more fuel from your tank as well.

Good Luck, keep us informed with your progress.

Pete

[redhead69]

Originally Posted by wild one

O.K. - first thing to do is move the metal filter from before the fuel pump to after the fuel pump.

Good Luck, keep us informed with your progress.

Pete

Will do on both.. good advice thanks

[djracer]

racing is like crack .................................................................................................... .................................................................................................... .................................................................but its legal!

[bigjimzlll]

Check your float levels.

[redhead69]

Originally Posted by bigjimzlll

Check your float levels.

Ive got the sight plugs the carb came with and manual says the level should be just below the viewing area, is this true for racing too or is there more to it?

[bigjimzlll]

Originally Posted by redhead69

Ive got the sight plugs the carb came with and manual says the level should be just below the viewing area, is this true for racing too or is there more to it?

IMO...that is just hogwash. Every engine is different. Try raising the secondary a 1/2 turn to start.
If you have a good fuel system then with your power it won't make any difference, but it is a good way to test if your fuel system is up to the task. If it picks up with the float adjustment, then you need a better fuel system

[scatesracing]

I would also try timing........ the reason i say that is mine was kinda the same way then i put nitrous onit like DJ told you to I took timing out for the nos and the damn thing picked up on the motor too.... so took out 2 more degrees i am now out ten dedrees and it has got faster every time... cant wait to get back too the track

[redhead69]

Originally Posted by bigjimzlll

IMO...that is just hogwash. Every engine is different. Try raising the secondary a 1/2 turn to start.
If you have a good fuel system then with your power it won't make any difference, but it is a good way to test if your fuel system is up to the task. If it picks up with the float adjustment, then you need a better fuel system

I will try this along with the filter and see, also I wired open my choke and seemed to help with a slight hesitation i was having as i was loading up.. I will keep you all updated, big race on Sunday- "Tulip Festival" paired with the "Winter Classic" because of a rain out. Should be a huge turn out on Sunday. Thanks for all the great ideas

keep on rockin in the free world

[chevy72blu]

Originally Posted by redhead69

Happy now.. got the mini spool in and she went straight today. First time Ive got to stay on it the whole track. I was happy with the way it launched but felt like it ran out of steam on the top end.. tell me what yall think heres was my best pass this morning

r/t .047
60' 1.939
330 5.712
1/8 8.976
mph 74.05
1000 11.888
1/4 14.384@89.49 mph

running a basically stock 406sb/th400 2500stall and 3.73 gears.. dot 28x10 slicks and hooked good. Doesnt my 1/4 mph seem slow for what I was running at the 1/8th??
Anyway I had a great day of racing and hope you all did too!! thanks for any input

eric

I tend to agree with what was said about the inline filter. A 4.11 gear would you a bit, but get your delivery issue sorted out first. That carb should be ample for what you are putting out.

As far as your times, that is pretty damn strong for the combo that you have.

What is your timing?

That 60' is really hurting you. You said you arent spinning, but I doubt you are over-tired with a 28x10. Sounds like you arent loading/launching the weight very well. What type of suspension are you running? Sure its not slipping?

[redhead69]

Originally Posted by chevy72blu

I tend to agree with what was said about the inline filter. A 4.11 gear would you a bit, but get your delivery issue sorted out first. That carb should be ample for what you are putting out.

As far as your times, that is pretty damn strong for the combo that you have.

What is your timing?

That 60' is really hurting you. You said you arent spinning, but I doubt you are over-tired with a 28x10. Sounds like you arent loading/launching the weight very well. What type of suspension are you running? Sure its not slipping?

Running stock trailing arm/coil setup with mentioned mini spool and your right Im hardly on the converter maybe 1500 basically because thats where i was cutting the best lights. Every time I went up more on the converter I was going red, just need practice. I thought about the 4.11s but then seen calculators for cruising speeds and since I travel about 60 miles round trip to race it the 3.73 seemed more logical for gas mileage. Kind of a balancing act driving it down there and going faster

[redhead69]

Originally Posted by chevy72blu

What is your timing?

Timing is set a 10deg initial with the vac advance plugged.. cant remember what total was. The mystery Ive had with my timing is the engine builder advanced the cam 4 deg (he swore by it with the 400's.). Not really sure what this does to my curve. I had it at 14 initial for a while and ran hard but was reall hard to start after it was warm.. bumped it down to 12.. power seemed close and after a good long run would occasionally still turn over slow.. 10 degrees and I run all day and starts good so I kept it there.

[Super73]

For my set up, 1/8 mph * 1.24665 = 1/4 mph fairly accurately.

So if this is true in your case 74.05 * 1.24665 = 92.315 mph.. You might be down a few mph.

As far as ET, my average multiplier is 1.5702.

8.976 * 1.5702 = 14.094

Again, you might be down on ET a touch too..

[djracer]

just spray it!

[70rs/ss]

700r4 will give you better (lower 1st gear and a higher 4th) stick with the 3:73 and you'll be good to go. I agree on the fuel as well bigger inlet, and maybe raise the float level a touch, but as said the fuel filter and line size should do it by itself, the trans and squeeze are further indicators of your addiction!! I have it too, but no track to take it out on. I drive 15 miles one way to work on a two lane road, not even a stoplight within 100 miles to even "play"!

[redhead69]

Well I tried just about everything we talked about and picked up a little. Cool! Ran super consistent all day dialed a 14.32 and ran a 14.326, then 14.324, 14.323 then broke out with a 14.312. Got faster all day but most people did (weather)! Thanks for all your help . Future upgrades will include a better fuel system, electric fan, and some stronger axles.

[Super73]

What did the rest of your best timeslip look like?

60'
330'
1/8 ET and Mph
1/4 mph

[redhead69]

Here is my times from the mentioned break out
r/t .147 (i hit snooze)
60' 1.925
330' 5.683
1/8 8.927@ 74.42
1000 11.824
1/4 14.312 @90.03

Here was my dash for cash run (best total package in time trials) I led the thing with 4 cars to go and got snubbed out right at the end
dial 14.32
r/t .019
60' 1.908
330 5.657
1/8 8.909
mph 74.21
1000 11.822
1/4 14.324@89.57

This is probably boring alot of you but im like a kid in candy store with this right now!

[redhead69]

Picked up quit a bit from last time I posted, Ive completely re-plumbed from the cell forward with-8 braided, new fuel pump, 3/8 aeroquip line from pump to a new 4150 650 dp (mechanical secondaries). Fuel filter is between pump and carb as suggested. Bumped the timing to 14deg initial which makes 34 right before 3k.
New best is 13.79 at 94.70mph. Seems to be running a little lean now but got to the track and back with more than a 1/4 tank (before I was stopping and refilling)

Big difference and goes to show how somethings are worth spending a little extra time and $$ on and doing it right the first time! Live and learn.

Im convinced that with an electric fan, no air cleaner, and some better exhaust I could get it to go 13.5's (maybe more with a GOOD carb).. very excited and wanted to share with you all since your such a big help and great inspiration!