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Author Topic:   gearing help needed
ss27
Dirt Full Roller

Total posts: 47
posted March 25, 2004 01:50 PM  
I am new to the mini stock class. I have a mustang that will be running on a 1/4 mile track. The car has a 4.11 rearend and P2356014 tires. Motor is fairly stock. Also what kind of RPM's will they turn.

bigcityracer
Dirt Freak

Total posts: 431
posted March 25, 2004 04:15 PM  
quote:
Originally posted by ss27:
I am new to the mini stock class. I have a mustang that will be running on a 1/4 mile track. The car has a 4.11 rearend and P2356014 tires. Motor is fairly stock. Also what kind of RPM's will they turn.

Need more info!! What gearing in the trans? If you have the 2.14:1 second gear you will be very close.


speedyd1
Dirt Maniac

Total posts: 170
posted March 25, 2004 05:29 PM  
you try that and you'll be looking for a new motor - that comes up to about 8.80 overall if my math is right. can you say broken rods, lifters coming apart and valves floating. shoot for something a bit more mild - say something like a 2.14 with a 3.08 or 1.99 with a 3.27. just my 2 cents. i would double check my rearend and confirm that you actually have that. big gear divided by small gear.ex. 37 / 12 = 3.08 (36 / 11 = 3.27 etc.)

bigcityracer
Dirt Freak

Total posts: 431
posted March 25, 2004 06:34 PM  
TES AND THAT'S ABOUT WHAT YOU WILL NEED RUNNING A 1/4 MILE TRACK WITH STREET TIRES WITH ABOUT A 79" ROLL OUT. LIKE I SAID NEED MORE INFORMATION. ALSO DEPENDS ON WHAT THE MOTOR CAN HANDLE. THAT'S ABOUT THE GEAR NEEDED FOR A STOCK ENGINE. I RUN A 8.44 ON A 3/8 MILE TRACK TURNING 8,200 ALL NIGHT. BUT MY MOTOR CAN HANDLE IT. I ALSO RANA WEAK MOTOR FOR 2 YEARS RUNNING 3.45 REAREND AND A 2.56 TRANS AND THAT CAR WAS QUICK OUT OF THE CORNER BUT WOULD ONLY TURN JUST UNDER 7,000.

b4racing
Dirt Forum Champ
Total posts: 626
posted March 25, 2004 07:17 PM  
I ran a stock bottom end on a 1/4 with the same tires as you. I ran the 2.14 and 3.45 rear. I ran it on small and big 1/4. Turned about 6800-7000. Just my .02 BObby

ss27
Dirt Full Roller

Total posts: 47
posted March 25, 2004 07:56 PM  
Don't know what Tranny is in the car, Know of a way to check while it is in the car?
I checked the rearend by truning the tire 1 turn and the drive shaft turned just over 4 times.



bigcityracer
Dirt Freak

Total posts: 431
posted March 25, 2004 08:58 PM  
Pull all your spark plugs put a wrench on the crank bolt. Turn the motor in second gear and have someone tell you when the rear wheel completes one full turn. That will be your final gearing. You can divide the rear gear to find out trans.

bigcityracer
Dirt Freak

Total posts: 431
posted March 25, 2004 09:01 PM  
quote:
Originally posted by b4racing:
I ran a stock bottom end on a 1/4 with the same tires as you. I ran the 2.14 and 3.45 rear. I ran it on small and big 1/4. Turned about 6800-7000. Just my .02 BObby


What size tires where you running? I was running 205-70-14 street tires with stock motor, other than cam change. I was coming out of the corners 4,000 and wouldn't climb past 6,900rpm. With a more horse you need less gear.

A group from my track went to another track and they all said the had more rpms, But my car lost rpms. There cars have more low end power and mine had high rpm power so mine needed more gear so it would come out of the corner in rpm range.

[This message has been edited by bigcityracer (edited March 25, 2004).]

b4racing
Dirt Forum Champ
Total posts: 626
posted March 25, 2004 09:10 PM  
I was running 235-60-14 all rollouts was btwn 72 and 76". I always set mine up to be more of a momentum car. You cann't win on the first lap was my philosophy and if you are gear bound by the flag stand you are not gaining anything. I was a little slow off the corner butinto and thru it I could not be touched. Again just driver preferance. Bobby

bigcityracer
Dirt Freak

Total posts: 431
posted March 25, 2004 09:53 PM  
Im sure your running a mustang with 2.3 or bigger. I run a 1.8 Toyota and you need to keep the R's up. Like I said I run it about 8,200rpm. I run foot to the floor and start to turn before releasing the pedal and don't use the brake, then back on the gas at the center. Never slide and scrub any speed off. It's the fastest car at the track by far.

daddyrich
Dirt Full Roller

Total posts: 33
posted March 26, 2004 06:14 AM  
i agree with speedy - unless you have swapped to solid lifters, you're gonna float valves at 7000 or better. those hydraulics arent gonna hold up. not to mention the stock rods. try it and see but dont be surprised to pull the valve cover and see the caps off your lifters or even a broke rod every once in a while. the stock cast pistons may crack and break on the skirt.definitely go with better pistons and try it. the 14's will definitely help.good luck

bigcityracer
Dirt Freak

Total posts: 431
posted March 26, 2004 07:38 AM  
Speedy1 and DaddyRich/ I due disagree but everyone has there own point of veiw and I know most track around here don't allow a lot of mods to the cars and with 2980lbs car running deep gearing is a must. With lite cars you can run a lot less gear. What size track do you guys run and what final gearing do you use? My current Toyota Corolla with driver is 2325lbs has a final gear of about 8.22:1 on a 3/8 mile (small) track.

Good Luck

b4racing
Dirt Forum Champ
Total posts: 626
posted March 26, 2004 11:01 AM  
that is the difference btwn the 1.8 and the 2.3 if you turned at stock 2.3 over 7500 you will make less power than if you let it work. I run a 2.3 I have also ran a little 1.8 toy and a 1.6 chevy. The little motors like the r's. but they are totally different animals. Again just my .02 Bobby

bigcityracer
Dirt Freak

Total posts: 431
posted March 26, 2004 11:59 AM  
I agree not turning over 7,000 with a 2.3 but if you have a heavy car you will need deeper gears to get it moving. I have ran my Capri 2.3 with a 2.56trans and a 3.45rearend and never seen 7,000 on a 3/8 track. That is running 79" roll out. I know most of you run 60 series tires with small 72" roll outs so my gearing seem way out of wack, but it's really not.

USAUS Racing
Dirt Full Roller

Total posts: 69
posted March 27, 2004 01:10 PM  
Do they make weak engines here or something?? I used to run an Australian motor (generalMotors Holden) with stock , psitons, rods and lifters at 10,000 in a rally car and never lost a vlave, pushrod, piston or rod - except for when I lost the oil sump. Engine size - 2.25lt..

racerman707
Dirt Freak

Total posts: 374
posted March 28, 2004 07:25 PM  
I agree!I turn my 2300 8000-8200 every weekend with stock rods,wisecos,stock crank,and NEVER floated valves.I changed rod bearings 4 times just for safety's sake.Hydraulic lifters will stand it if you know how to do it.Only problem I had last year is we melted a piston due to too much timing.I'm going to a lower gear next year by the way.

racerman707
Dirt Freak

Total posts: 374
posted March 28, 2004 08:08 PM  
Oh yeah,I run a 6.14 limited slip 8.8 in 4th gear with 79" tires.Last year I ran 2.14 trans with 2.73 gears(same tires).Turned 8000 last year but have not tried it this year yet.

daddyrich
Dirt Full Roller

Total posts: 33
posted March 29, 2004 07:00 AM  
we run 1.99 and 3.08 in our stock minis and 2.14 and 3.27 in our modifieds. the stocks stay with hydraulics and the mods run solid rollers. i build these motors for a living and have seen just about every combo you can imagine. the 2.3 stock motor is fine up to a point but if you push it you'll have problems. thats not to say there arent exceptions to the rule. i've seen motors pulled from junk yards with 200 thousand miles run up front and keep on truckin. does that mean that they are better than our 2000.00 stock motors. not hardly. it just means you got lucky. and as everyone knows luck runs out sometimes. the 1/4 mile track he is running certainly requires the rpms to be kept up but you must keep in mind that the stock cam in those motors will reach peak torque at or about 4500 - 5000 and if your coming off the corners any higher than that your just p****** in the wind. we've dyno'd them several times with several different ratios and found they respond better under load when operating at or about its peak when exiting the corners. my suggestion would be to lose the 14 tires and run the 13's and keep the final at 6.20 to 6.50. 6500 to 7000 at the end of the straights will do fine.

racerman707
Dirt Freak

Total posts: 374
posted March 29, 2004 06:57 PM  
Luck has nothing to do with it.You can't come to the track and turn no rpm and expect to keep up.A good hydraulic head will turn 8000 to 8300 and make good power.The thing is it has to be right.

daddyrich
Dirt Full Roller

Total posts: 33
posted March 30, 2004 04:12 AM  
i give in - youre right / i'm wrong. run that thing all you want. hope you do well. i guess i'll just go back to the shop and build some more wrong motors. maybe i should call esslinger, racer walsh, race engineeering, johnson machine and everyone else we deal with and advise them of our misgivings. its a real shame that we all have spent the last 20 years doing it the wrong way. i guess its not too late to start over. maybe i'll just sell our dyno and our sunnen cnc equipment and start cycling or something. i here the whole gearing question isnt so hard over there. aint life great. good luck and turn em tight.

racerman707
Dirt Freak

Total posts: 374
posted March 30, 2004 10:41 AM  
This forum is full of opinions.I never said you were wrong,all I said was I turn my hydraulic 2300 motor 8200 every weekend.It can be done and done reliably.If anyone deals with Esslinger they will tell you that they have got these rpms out of hydraulic heads.Say what you want,if you are limited to hydraulic lifters you must do what it takes to get the most available power out of them no matter what anybody says won't work.By the way my brother in law runs a johnson machine hyd cam and turns 7800.

juliaferrell
Dirt Freak

Total posts: 370
posted April 05, 2004 10:42 AM  
I think with low spring pressure (seat at about 80) you can take the hydraulics to 7500. If you think you're turning eight thou with hydraulics get your tack fixed.?? I've had the cheater hydraulics and 75 to 77 is about it....As for the gear on hydraulic 3.4 and a 2.00 tranny is the way to go....pitch the 14's in the trash.

ss27
Dirt Full Roller

Total posts: 47
posted April 05, 2004 01:46 PM  
Why trash the 14's

racerman707
Dirt Freak

Total posts: 374
posted April 05, 2004 07:41 PM  
Go ahead and run 80 pounds seat pressure and you'll float the valves at the flagstand.I use more pressure on hydraulics than solids.No need to get rid of 14s just get your gear right.

b4racing
Dirt Forum Champ
Total posts: 626
posted April 05, 2004 08:22 PM  
I run 110 pressure on my 2.3 racerman is right about floating them if you do not. Later Bobby

ss27
Dirt Full Roller

Total posts: 47
posted April 05, 2004 08:29 PM  
What are you talking about with seat pressure?

racerman707
Dirt Freak

Total posts: 374
posted April 06, 2004 09:37 AM  
How much pressure is on the spring with the valve closed.

tay27tronnie
Dirt Full Roller

Total posts: 37
posted April 15, 2004 05:19 PM  
As far as the rear gear take the plate off the rearend and look what is stamped on the big ring gear. That will tell you what gear you have on the rearend. And listen to bobby or speedy1 espically speedy, Because you can have the wrong gear in it and BLOW IT ALL TO PIECES. Make sure what your running gear is.Your cam and motor has to with stand what your right foot does.

popeye14709
Dirt Forum Racer

Total posts: 86
posted April 20, 2004 06:42 PM  
We ran last year a completely stock 2.3 on a 1/3 mile track and was pushing 6600 r's and thats running 205 70 14's on the right and 195 70 14's on the left our rear gear was a 3.50 this year were going into solid lifters and cam and had head and block worked by a repitable builder this year we are garenteed by the builder 8000+ r's, the Track owner has made up a track tire rule 185 or 195 70 14's not sure what it is if your running 13's

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juliaferrell
Dirt Freak

Total posts: 370
posted April 20, 2004 07:27 PM  
80 pound of seat pressure works fine. Isky D springs is all you need with a WG5022 blue racer cam. I've raced all over with hydraulic rule classes and haven't seen anyone come close to the rear bumper. Put your 14's on and come on down. CG up so high you might as well be in 4wd. Can't touch the Hoosier DOT with any 14 inch tire that I know of. The Racing recaps are has beens. hehe

juliaferrell
Dirt Freak

Total posts: 370
posted April 20, 2004 07:36 PM  
That's 80 pound of seat pressure with the lightest valve on the market (.214 stem) You can't do that with stock or those stainless 1.89 1.59 setups. Sorry not to get the facts straight.

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