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Author Topic:   couple more ?
Whitelightning
Member
posted March 30, 2003 01:38 AM
Ok here is the scenario. fresh motor runs really strong all new shocks and springs and I finally get it handling good. I am simply getting out run. I am running a 3.42 gear with a automatic turbo 350 in second gear. Just about every one else runs same tranny a second gear but they all say they run 3.73. Keep in mind this is 1/2 mile dirt track. My question is will changing gears from a 3.42 to 3.73 be that big of a change or should I look else where. I really notice that looking at the other cars as the pick back up the trottle its like there rpms are already built up upon exiting the corner versus my car is not turning that hard so soon but yet the engine really seems to make good power.Any takers help will be appreciated


Eljojo
Member
posted March 30, 2003 04:54 AM
The way I "cypher", your 350 turbo has a 1.52 second gear. Running the 3.42 rear will only give you a 5.1984 final drive gear. The 3.73 rear end ratio will final out at 5.6696 that's dang near a half-point difference in ratio. You might be able to overcome the ratio difference by using a very small tire. I've wondered what a set of those 45 series tires would do on dirt.....I KNOW they'll kick asphalt! If it's a metric chassis you can "trick" the chassis into thinking it's suspended normally while the ride height is very low.


teamstertom
Member
posted March 30, 2003 06:01 AM
Todays street stock motor program is just not a "stock" motor anymore. The front runners will tell you that their motor is stock and made up of stock pieces,but what you can't see is what you can push the rules with.

The biggest key to keeping up those rpm's and being able to mash the gas so your rpm's don't drop so fast is light weight pieces in the bottom end of that motor. Lite weight crank,rods and pistons are reasonable priced and racers are using them.

Did you do anything to the HEI? People tend to just drop it in and think it is good to go,but it may need a trick or two. Another area is carb,the gas has to flow. Some simple upgrades will increase performance like you wouldn't believe.

Tire spin....did you have tire spin and you were noe getting the traction you needed? Next time,have yourself or a crew member put a hand on the rear tires ans feel the warmth of that tire,and check air pressures right away. How much air pressure was gained? That alone will help you tell if tire spin was a problem.

I think it was you in another post talking about being warm. I do not worry about 190 to 210. Just acouple of things to look at....if you are running a 3 or 4 core stock piece,is it flowing freely? If you do not think so,have it hot tanked and cleaned. What type of water restrictor do you have? Was the block and radiator full of water? No air in the system? What pound cap are you running?

gould
Member
posted March 30, 2003 06:35 AM
most guys around here in the hobby stock class on a half mile track are between 5.67 to 6.00 for a final drive. how does that 350 turbo work? im putting one in my hobby stock and everybody says im a sitting duck. lol. ill be running half mile with a 2.27 gear and tranny in first. comes to 5.72.gould


racer17j
Member
posted March 30, 2003 01:06 PM
gould i'll tell you next week how that set up works becuase thats what i have in right now too last year i ran a 3.23 and like you lightning i was way under what every body else was running they all run3.73-4.10 i can tell when they go by that they are turning about 1000 or more rpm then me and everybody comes off the corner much better than me unless it's sloppy then i leave them because they spin the tires coming off and i don't. one other thing i didn't like is it's alot harder to work traffic when it takes longer for it to get wound up i did 95% of my passing last year going into the corner and then doing a slide for life to try to keep from getting pulled off the corner again


Whitelightning
Member
posted March 30, 2003 04:06 PM
has far as the tranny I have ran it going on three years no problem, very few have manual trannies in my class it almost more of a pure stock class, and even tough it dont seem to be the case I really think that my engine is every bit has strong has the front runners but apperently its not but has far as tire pressure gain it gained a 1/2 pound in all four tire in a 8 lap heat race but in a 15 lap feature the right front 1 1/2 pound gain, rr 1 1/2 pound gain, left rear 2 1/2 pond gain left front 1/2 pound gain, but to me it really seemed to handle good the only time I can pass is in the corner cause I have to run in harder.


Whitelightning
Member
posted March 30, 2003 04:12 PM
also about the temp ?teamstertom, I have a regular termastat and I cut the center out and used it has a restrictor, also I have to look at cap im not sure what pound it is but what should it be? I do run the 4 core radiator and it ran 190 all night until the feature but in the feture my power steering blew and the fluid soaked the front of motor could that cause the belt to slip not causing fan to spin properly or not?


teamstertom
Member
posted March 30, 2003 06:44 PM
I run the 5/8 water restrictor with a Stant 22-24 lbs cap. You are right about the slippage with that oil all over,temp will rise with that problem. Your air pressures seem okay. On my track,a 1/3 mile semi banked(wet and sloppy to a dry slick at feature time)I run a 4:10 gear with a Turbo 350 in second gear,perfect combo. Never had a trans fail yet. The tire we run is a Hoosier RC4 with very little dia. change,so off sets and air pressure make the difference when it comes to setting up the car. To better your car,be careful not to change a whole bunch of things. Change just a few at first to realize what change has done what.


wermm
Member
posted March 30, 2003 09:53 PM
I ran a turbo 350 in second with 3.73 gears on a half mile with very long staights and tight turns. I would get pulled a little off but by the end of the straight we were hitting 6500 and running times almost the same as the guys with 3 speeds. If the other guys in your class are running 3.73's it would be a wise move, in my op. Good luck in what ever you decide


Whitelightning
Member
posted March 31, 2003 09:57 AM
also my hei is stock, would that be a problem of only hitting about 5000 at the end of straits because I can run 3000 just riding around out there but cant turn over 5000 at the end of the straits


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