gearing

[deepindebt]

Question for you dirt guys, what type of gear change do you make from Bonneville to Elmo if any? We run a 2.79 on the salt, have a 3.0 that i was thinking would be good for the dirt, then i got to thinking that due to the lack of traction on the dirt that we may just blow the tires off with the lower gear? Thoughts?(4 speed manual)
Thanks

[SPDRACR]

El Mirage gearing should be done for the record attempt. Tire slippage is controlled by your right foot.
Is your roadster with your Bonneville gear capable of pulling that gear in a 1 3/10 miles.
Our roadster is currently a 2.91 for El mirage and a was going to be a 2.47 for Bonneville but we know how that went.   

[Stan Back]

Here's a longer echo from the above . . .

This is from our team's 8 years of setting C and D Street Roadster records with a 4-speed at both events.

First was Bonneville.  What's the record?  Our motor tops out at 7500(?) RPM.  We want to be almost near that at the 4 so we can maintain that for a full mile.  Do the math and select a gear that might do that and find out if that works. After a few years, make a little more horsepower and add in some gear.  After a few years, we went from (as I may remember) a 3.10 to a 3.00 and it took a lot of work to finally max that one out.  Keep good records of what exactly you're doing each run.

Now we're at El Mirage.  What's the record?  We want to be at our peak horsepower at 1.3 miles for a very short time.  From experience, the lower gear may spin the tires at launch and more.  Give it a higher gear, and it may never get into 4th but the driver doesn't have to do anything but change gears.  Whoops, missed again.  Maybe the driver has to "drive".  Taking off in 2nd takes the oneness off his responsibility and slows down the whole process.  Maybe never get in 4th, never get the record.

Figure out what RPM you need and either drive better or add horsepower.  Or just keep rear gear changing to get your best speed with what you got.  Enjoy the circus.

Stan Back   

Attached your file... maybe...

[deepindebt]

Great info and killer record keeping Stan, i think for our first trip we will keep the Bonneville gear in and feel it out since I'm sure due to rookie passes we wont be allowed to drop the hammer anyways.
Thanks for the info from you both.

[Stan Back]

Thanx to Stainless for posting our chart.  A few explanations are as follows . . .

Pill -- Size of Hilborn bypass return line jet, adjusts lean or rich.
Temp. -- Temperature at time of run.
Alt. -- Relative altitude air pressure.
Meter -- Mysterious Black Box handed down from engine builder -- probably taking Alt. and Temp. numbers giving a relative rating.
Pyro -- Pyrometer high temperature average of each bank -- only one sensor on each V-8 bank.
Speeds -- As noted.  El Mirage at speed trap.   

[deepindebt]

I must say with that size on our return we would have some melted pistons. All engines are different for sure.
Thanks again

[jl222]

  Traction is actually better look at the streamliner 305 mph and lakester 308 mph records.

   Our 222 Camaro has gone. 270 mph in 10.3 sec but loses traction shifting into high gear when the marbles arrive.  Overall gearing is 1.85 same as Bville. Not possible to accelerate that fast at bville not shiffting into high until after the 1st mile

  Alot of course blame is on tire spin but I believe part of the problem is vacuum from underneath and rear of cars sucking the pebbles out of the dirt cracks.

  YEARS ago on course duty, the Swain Bros Helash and HOOVER a 280 mph blown fuel modified roadster hit some cones.

 Looking at the tire tracks, clear, about 4'' wide, no tire spin but behind the car the pebbles looked like someone was casting out chicken feed or sewing grass, Like 1st one way and then the other.

 At the Nov 2 day meet were leaving the trans in 3rd gear and not shifting into high.

   JL222

[jl222]

Thanx to Stainless for posting our chart.  A few explanations are as follows . . .

Pill -- Size of Hilborn bypass return line jet, adjusts lean or rich.
Temp. -- Temperature at time of run.
Alt. -- Relative altitude air pressure.
Meter -- Mysterious Black Box handed down from engine builder -- probably taking Alt. and Temp. numbers giving a relative rating.
Pyro -- Pyrometer high temperature average of each bank -- only one sensor on each V-8 bank.
Speeds -- As noted.  El Mirage at speed trap.

 JIM what about port nozzels?

               JL222

[deepindebt]

Good ifo jl222, thanks and you know Jim wont give up all his secrets plus we are direct injected at the head so a different set up! See you in Nov

[Stan Back]

The nozzles were deep in the injector manifold -- as from the factory.  Can't remember right size.  I took the pump every year to the factory and had them test it.  Once in a while they'd put some new hardware on it and say it was fine.  Then gave me a T-Shirt and I'm on my way.

Never made a lot of runs.  Got there and made a run, looked at the results, modified if necessary and ran again.  If the course was shit, said hello and went home.  The chart lists every run we made at each meet.  The first time out in the car, this with the D motor, made initial run to the 3 to get to the long course, then 2 runs for the record and packed out.  None of which was due to my knowledge about anything, but having a lot of knowledgeable friends.   

One time I listened to some well-known competitors who told me that I'd gain a bunch of HP by relocating the nozzles high up the injector tubes.  Made one run and pulled out at the 5.75 (never used a chute -- too much trouble) and looked at a real neat pink flame pattern covering the cowl.  Raw racing gas.  Went slower.  Didn't try that again.

Speaking of brakes.  Had the car 57 years and long ago went thru the Ford brakes front and rear to see if it would get to stop easier on the street.  I'm not an expert at that, but did my best.  I was able to lock one front one -- progress!  After changing the machine back to a race car with only some wide Thunderbird(?) back shoes on it, it stopped much better than ever.  I'd trust the 2 of them to be much better than 4 of the 1939 Fords.  But by then there was 60% of the weight in the back, hard to do with 10% set-back.         

   

[deepindebt]

When we went with our new set up i thought that having the nozzles up in the manifold would be better for atomization, well Kinsler said do what you want but you're throwing 20hp min out the window by NOT going in head, we never tested on dyno but they are way smarter than me.. Never got any shirts either!!

[deepindebt]

Update, killer trip, Elmo is a hoot. SCTA was great, weather was great (COLD) Friday we went through insp and did our first rookie orientation, went great, Saturday we had to do our second RO and watch cars leave the line, all good. Went back to our pit and started heating the oil and getting ready to run. Once the oil was warm we primed the oil and fuel, hit the starter and the stater said not today!! We have a spare so we did that fun job. Not easy on our set up. Got the new starter in and fire the car, all good. Towed to the rookie line, moved pretty fast. First pass needed to be under 150, we went 144, all good. Course was total crap so they called it and moved to a new course for Sunday. We got in line early and again the rookie line was moving. Next pass needed to be under 175, we went 172, perfect. We know the course was getting bad as the runs continued. Our plan for the next and last pass which needed to be below 199, we figured lets use 4th gear this time(used 3rd on the 2 previous runs) that way we would be more lugging and less tire spin, we came up with 6500ish put us at 195, looking back that was probably a little greedy and didn't need to go that fast. Anyways it was going great until it wasn't, i was peddling all the way down the course , hit 4th, got to my desired RPM, a little more peddling and then she just snapp spun on me. I unfortunately took out the left side timing lights and did some damage to the car but considering, all is good. SCTA was super cool, i was pretty bummed but then they reminded me what i drive, This was my first spin and i have been driving this car since 2003, it happens. I feel i did good getting her stopped and my son did a killer job in the push truck, that was his first time. All and all a great experience and we learned a lot. Thanks to all.

[jl222]

  Traction is actually better look at the streamliner 305 mph and lakester 308 mph records.

   Our 222 Camaro has gone. 270 mph in 10.3 sec but loses traction shifting into high gear when the marbles arrive.  Overall gearing is 1.85 same as Bville. Not possible to accelerate that fast at bville not shiffting into high until after the 1st mile

  Alot of course blame is on tire spin but I believe part of the problem is vacuum from underneath and rear of cars sucking the pebbles out of the dirt cracks.

  YEARS ago on course duty, the Swain Bros Helash and HOOVER a 280 mph blown fuel modified roadster hit some cones.

 Looking at the tire tracks, clear, about 4'' wide, no tire spin but behind the car the pebbles looked like someone was casting out chicken feed or sewing grass, Like 1st one way and then the other.

 At the Nov 2 day meet were leaving the trans in 3rd gear and not shifting into high.

   JL222

  270mph in 10.3 sec? I wish  170 in 10.3 sec only off 100mph


                JL222