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Re: Foot brake or flash the converter? [Re: DodgeCharger] #565645
12/30/09 08:04 AM
12/30/09 08:04 AM
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Posts: 27,421
Balt. Md
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383man Offline
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I like to come up on the converter some. My 63 seems to launch it's best bringing it up to about 2200. And the car reacts faster this way. Nice Cuda and cool pics. Ron

Re: Foot brake or flash the converter? [Re: 383man] #565646
12/30/09 09:23 AM
12/30/09 09:23 AM
Joined: Dec 2007
Posts: 310
Michigan
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412 SB Duster Offline
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Michigan
With only being able to run on roads and at airports and not a dedicated track is making it a lot harder to dead hook the car. I would look at taking some hit out of it at the line, change the cam or move it. Go for more of a big end charge like the fast class racers do.
Ever try Q time pros they seem to work well when I ran them on the street, real soft compound.

Re: Foot brake or flash the converter? [Re: 412 SB Duster] #565647
12/30/09 02:37 PM
12/30/09 02:37 PM
Joined: Nov 2009
Posts: 520
New Zealand
nz383man Offline OP
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Quote:


Ever try Q time pros they seem to work well when I ran them on the street, real soft compound.




I bought Quicktimes rather than Quicktime pro's because we are not allowed to run Quicktime pro's on the street in New Zealand & a couple of places we race are close enough to drive to on race tyres.

The best thing about a bad track is it's bad for everyone! I'm staarting to beat people on 1/8 miles that are concentrating on HP rather than hooking their car. For a factory stock car I hold my own OK on 1/8s but I don't have the charge for 1/4s.

Some of the late model Aussie sedans take some beating, the Holdens (307kw/411hp) & Falcons (317kw/425kw) go like hell & use traction control

DodgeCharger you wrote -


I would start working with rear tire pressure and loosen up the front of the car to get more weight transfer.

I'm running anything from 10-14psi I always run 14psi on the first run of a 1/4 to see how the car feels at the top end (remember roads, bumps, hollows etc) then they usually gain a couple of psi with heat so I drop down to 12psi (hot) & see how it runs. I take notes of every run I do. I really need to get in some decent testing at different pressures.

I'm running 275x50x15 Hoosier Quicktimes on 10" rims, would the sidewalls work better on a narrower rim? Hoosier say 8"-10" & 9" is best. I only use the 10" as they are what I could get, my car normally runs factory 14" Magnum 500s.

Any more ideas on loosening up the front? I have 318 torsion bars, Summit 90-10 shocks, factory length bump stops, factory bushes, joints etc

Thanks for the input everyone & keep it coming

Re: Foot brake or flash the converter? [Re: nz383man] #565648
12/30/09 07:43 PM
12/30/09 07:43 PM
Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
DodgeCharger Offline
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The 6 cylinder bars would give you more reaction then the 318 bars but the car wouldn't handle as good on the street. Also you could either trim or remove the factory bump stops. I think some on here have tricks on loosening up the stock bushings but I don't remember what they are. Many recommend using worn bushings since they aren't as tight as new stock. The more front end travel the better.

Re: Foot brake or flash the converter? [Re: nz383man] #565649
12/31/09 07:05 AM
12/31/09 07:05 AM
Joined: Nov 2009
Posts: 520
New Zealand
nz383man Offline OP
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I'm running 275x50x15 Hoosier Quicktimes on 10" rims, would the sidewalls work better on a narrower rim?
Hoosier say 8"-10" & 9" is best.

Any suggestions?

Re: Foot brake or flash the converter? [Re: nz383man] #565650
12/31/09 07:17 AM
12/31/09 07:17 AM
Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
DodgeCharger Offline
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The tire might work better on a narrower rim. I never heard of a 275x50? only a 275x60. But I think the improvement you might see in a narrower rim would be the tread surface. With a wider rim the tire will tend to cup in the center quicker and ride on the sides of the tread.If you go to a narrower rim you should be able to run lower air pressure with better tire surface contact to the road. But the only way to find out for sure would be to test on 8 inch rims.

Re: Foot brake or flash the converter? [Re: nz383man] #565651
12/31/09 01:44 PM
12/31/09 01:44 PM
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Posts: 19,318
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Thumperdart Offline
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I`ve been beating/tweeking my car for years and my new combo which is a 470 bb stroker w/an 8" vert likes a 3000 rpm leave for the best 60ft/et. If you climb too far up in the r`s at the line you will start seperating the suspension and yes it is planting the tire somewhat but it`s also limiting the useable travel so whatever. I run 6-cyl bars but my car is lighter than yours and they work good for me on the street as some say they won`t. Too many variables......loosen the ft. as much as possible,play w/tire pressures launch etc. and the et`s will come.

Last edited by Thumperdart; 12/31/09 01:45 PM.

72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Foot brake or flash the converter? [Re: Thumperdart] #565652
12/31/09 04:11 PM
12/31/09 04:11 PM
Joined: Aug 2003
Posts: 43,349
Bend,OR USA
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Bend,OR USA
Every car and track are different so you have to experiment to find the best methods to use on your car, sorry that I can't give you the exact methods to make your car hook every time Don't forget that as the track gets more runs on it during the day that it may (probally) will change later in the day so what work in the morning may not be the best procedures to use in the race later in the day BTW, I had a 1970 Barracuda that I used to race in NHRA A/S, it had a hemi in it The weight distribution was very similar but worse than yours 2160 lbs on the front and 1290 lbs on the rear with no driver and half a tank of fuel 4 speed on nine inch tires As far as tire width and rims you might want to get a extra set of rims and drag race only slicks to use at the track only I have several sets of M/T ET Streets and ET Street Radails on ten inch and twelve inch rims. My car is a "street car" that I built to race the high dollar street racers in Los Angles before I moved to Oregon ( I never got to do that ) so I wanted it to look like a not so serious race car, hence the "street tires" The point I want to make is it will run the same ET and 60 ft. times leaving at 1200 rpm or at 2300 RPM, this is the first car(out of 12 or so automatic cars) that I have raced that is this way Most of the others like a higher stall,2300+RPM, especially the dedicated race cars with 8 or 9 inch converters. My current car has a custom built 10 inch converter, it has gone as fast as 10:43 at 128.9 MPH with that converter in the 1/4 and 6.86 in the 1/8, best 60 ft was 1.43 so far. The motor is a 518 C.I. pump gas (10.29 to 1 comp. ratio)low deck stroker in a 3450 lbs.1971 Duster with me in it with the 315x60x15 ET Street Radials on ten inch rims on the ladder bar rear suspension with coil overs. IHTHs , don't forget to test, test, and test some more.(write every change and the results down after every run, don't wait until the end of the day or the next day Please keep us posted with your results

5700612-MVC-045S.JPG (30 downloads)

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Foot brake or flash the converter? [Re: Cab_Burge] #565653
12/31/09 05:59 PM
12/31/09 05:59 PM
Joined: Nov 2009
Posts: 520
New Zealand
nz383man Offline OP
mopar
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Posts: 520
New Zealand
Cheers Guys, & Happy New Year, you are getting me very inspired to spend my holidays "Testing"

DodgeCharger
“The tire might work better on a narrower rim. I never heard of a 275x50? only a 275x60.”

I'll keep my eyes open for some narrower rims.
I went with the 275x50 as they have a 1" wider tread than the 275x60 & to keep the gearing lower.

Thumperdart
“If you climb too far up in the r`s at the line you will start seperating the suspension and yes it is planting the tire somewhat but it`s also limiting the useable travel so whatever.”

OK, good call & I have a plan to check it, if use a remote tacho & a yard stick at each wheelarch I could video the rise relating to the revs on the converter in my garage, idle to 2600.

“Too many variables......loosen the ft. as much as possible,play w/tire pressures launch etc. and the et`s will come.”

I'll see what I can do with loosening the front, shorter bumpstops, research bushes etc. Would I be better to go to a pivot style joint on the track rods rather than the factory rubbers, as the rubbers do seem to limit movement a bit.

Cab_Burge
“don't forget to test, test, and test some more.(write every change and the results down after every run, don't wait until the end of the day or the next day Please keep us posted with your results”

Yes, this is great advice & I do follow it. I would like to test more (who wouldn't) but I do take notes straight after every run & have pads of notes & excel spreadsheets that I refer back to all the time.

Some of you may thing I'm getting a bit carried away for such a slow car but I want to keep it factory stock looking but go as quick as I can. I am beating quite a few faster cars already on the 1/8 due to the fact I'm getting quite a bit of my power down rather that have more power & go up in smoke. I am collecting parts for a much stronger (stock looking) 383 so more power is the next goal.

Re: Foot brake or flash the converter? [Re: nz383man] #565654
12/31/09 06:32 PM
12/31/09 06:32 PM
Joined: Apr 2004
Posts: 1,981
SE Michigan
TS3303 Offline
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SE Michigan
whether you flash it or leave on the converter depends on the suspension and weight transfer of the car. If it doesn't transfer weight quickly it will most likely want to be flashed to get the extra momentum of hammering against the stall of the converter. How much hammering it will want will take testing. On a light chassis car like Mr P said it usually doesn't like to be hammered against the stall. Mine is most consistent and smooth if I leave off the converter or 100 rpm's below.

Re: Foot brake or flash the converter? [Re: TS3303] #565655
12/31/09 07:19 PM
12/31/09 07:19 PM
Joined: Aug 2003
Posts: 4,055
Salina ks
572_dup2 Offline
Back On The Bumper!!
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Salina ks
My car has always seemed to leave its best around 2000-2200.


Shawn Jennings
Re: Foot brake or flash the converter? [Re: 572_dup2] #565656
01/01/10 02:33 AM
01/01/10 02:33 AM
Joined: Nov 2009
Posts: 520
New Zealand
nz383man Offline OP
mopar
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New Zealand
I tested the wheel arch height v RPM on the converter, sorry the heights are in mm but that was easier for my good lady to measure.



RPM LF RF LR RR
Off 613 617 613 617
800 615 614 618 617
1000 615 614 618 618
1200 615 614 618 618
1400 620 610 620 615
1600 620 610 622 615
1800 622 606 625 612
2000 625 606 627 612
2200 626 603 629 610

Re: Foot brake or flash the converter? [Re: nz383man] #565657
01/01/10 07:22 AM
01/01/10 07:22 AM
Joined: Jul 2004
Posts: 4,384
Worst Weather USA
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BG and FRED --- DONT GET ANY IDEAS






Re: Foot brake or flash the converter? [Re: nz383man] #565658
01/01/10 08:03 AM
01/01/10 08:03 AM
Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
DodgeCharger Offline
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Mohnton, Pa
Some of you may thing I'm getting a bit carried away for such a slow car but I want to keep it factory stock looking but go as quick as I can. I am beating quite a few faster cars already on the 1/8 due to the fact I'm getting quite a bit of my power down rather that have more power & go up in smoke. I am collecting parts for a much stronger (stock looking) 383 so more power is the next goal.



When you get ready to build that new more powerfull stock looking 383 you should ask for ideas from this board. The number one priority for your build would be to stroke the motor.The more cubic inches the beter. I seen a T/A Challenger at our local track a few years back that looked completely stock right down to the stock Polyglas tires. The car ran high 11'. I later found out the owner was a FAST racer. These are the guys that can help you out. They run faster on stock tires that many run on slicks.

Re: Foot brake or flash the converter? [Re: DodgeCharger] #565659
01/01/10 06:24 PM
01/01/10 06:24 PM
Joined: Nov 2009
Posts: 520
New Zealand
nz383man Offline OP
mopar
nz383man  Offline OP
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Posts: 520
New Zealand
When you get ready to build that new more powerfull stock looking 383 you should ask for ideas from this board. The number one priority for your build would be to stroke the motor.The more cubic inches the beter. I seen a T/A Challenger at our local track a few years back that looked completely stock right down to the stock Polyglas tires. The car ran high 11'. I later found out the owner was a FAST racer. These are the guys that can help you out. They run faster on stock tires that many run on slicks.




Yea, you are on the same page as me, I want to build my car like a FAST car (without polyglass tyres) while keeping it streetable & having fun beating a few Fords & Chevs with "built" engines.

Re: Foot brake or flash the converter? [Re: nz383man] #565660
01/02/10 11:23 AM
01/02/10 11:23 AM
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Posts: 598
NC, USA
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Caveat...I am no expert racer...

It looks like you are getting a fair amount of torque roll in the body when bringing up the RPM. If you can keep the back more even, you should get better traction. I don't think the 70 cuda had a rear roll bar option, but the later ones (72-74?) did. I'm curious if anyone else thinks that addition of a rear roll bar would help.

Dave

Re: Foot brake or flash the converter? [Re: davenc] #565661
01/02/10 01:52 PM
01/02/10 01:52 PM
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Posts: 19,318
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Thumperdart Offline
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And that was my point about bringing the r`s up too much and seperating the suspension. That`s where a trans break comes in handy.......no suspension seperation and hits the tire harder although a t-brake is probably out of the question in your case. I foot brake my car but next time around I may go w/ a t-brake.


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Foot brake or flash the converter? [Re: davenc] #565662
01/03/10 10:08 PM
01/03/10 10:08 PM
Joined: Nov 2009
Posts: 520
New Zealand
nz383man Offline OP
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New Zealand
Quote:


Caveat...I am no expert racer...

It looks like you are getting a fair amount of torque roll in the body when bringing up the RPM. If you can keep the back more even, you should get better traction. I don't think the 70 cuda had a rear roll bar option, but the later ones (72-74?) did. I'm curious if anyone else thinks that addition of a rear roll bar would help.

Dave




OK I'm curious what others think about a rear anti sway bar as well or should I go to SS springs? are the Mexican made SS springs any good or not?

Thumperdart


And that was my point about bringing the r`s up too much and seperating the suspension. That`s where a trans break comes in handy.......no suspension seperation and hits the tire harder although a t-brake is probably out of the question in your case. I foot brake my car but next time around I may go w/ a t-brake.

While out of town on holiday with my lady I did do a few flash the converter starts which showed the time I spent converting my Carter AVS to annular boosters was well worth the trouble.

The next time I race I'll do 2 or 3 runs footbraking to get a benchmark then try flashing the converter.

From the feedback I'm getting here I may need to footbrake where traction is bad & flash the converter where traction is good.

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