Drag Racing Discussions > Front Engine Dragsters
Jr Fuel tire diameter
Scottmech:
John.....Yep...that's the way my car was set up originally. Motor was set back 7 inches from it's current position. They pushed it out for the glide at some point.
I ended up going back to the 30 inch tire. Tried the 33's to gain ground clearance and lower rpm at line, but the car looked like a cartoon. Lol. Tires were too tall which also made the tire too wide. Ended up going back to the 30 inch tire. Looks much better, and it handled great.
Car ran good first time out. Did a good shakedown run then opened it up after. Wasn't hitting it hard off the line cause still getting used to it, but ended up running 9.3 at 152. Basically they were high gear runs cause I didn't go WOT till it was in 2nd about 1.5 sec into the run.
This pic is the car with the 33's....
Here it is with the 30 inch tires.
JrFuel Hayden:
Your high gear launches should be hard on your PG clutches, just try 1'st gear launch then shift early, like 60' out, while you are getting used to the car.
What 30x10.5x15 tire are you using ? And any idea what kind of HP you are making ?
Have Fun !
Jon
Scottmech:
I'm not launching in 2nd gear, launching in 1st.
I considered the first runs "high gear" runs because by the time the front end got loose, I let off the throttle let it settle, and then got back into it, the car was all ready into second gear at which time I was WOT.
The trans is a fresh BTE unit with SFI case and was built to handle a blown alcohol 7.0 car. I doubt there's much my little NA 355 can do to it.....lol.
Estimated hp from weight and trap speed is 410-425 at crank. Which matches other testing I did when engine was in my other car.
Slicks are M/H 30x10.5x15.
Ran the car this past weekend. Was happy with the progress, but it has a slight intermittent miss that's been there since I built it. Think I know where the problem lies and have a plan to address it before the next time out.
Here's a pic from this weekend. A few feet off the line.
Had some goals for the car before the build began. Wanted something that looked mostly period correct (minus the updated chassis and clothing). Had to be able to run it on my own (self start), which means it's driven to the lanes and back to pits. Didn't want a cooling system or batt on the front of the car, and under no circumstances will it run it with a wheelie bar. Yeah, I know it wont be able to push the limits coming off the line without one, but I'm willing to accept that for the sake of looking a little more period correct.
The plan is to run it on an 8.5 or 9.0 index.......the latter being more likely on straight alky, and 8.5 with a little pop, which the motor will easily handle. It was making and easy 650+ hp in my Fiat with a blower....so I figure there's plenty of room for a 20% load....and possibly as much as 40%, which is about as much as I can run being a self starting car (as per recommendation from Spud). Though I doubt I'll ever run it with 40...
So far most of my goals have been met. Am confident the remaining goals (better ET) will come around as I get used to the car and learn what it likes.
JrFuel Hayden:
Scott, it sounds like you need to add some ballast to your front axle, to help balance your car to keep the front wheels down. You can't win races if you can't steer your car. I would run a wheelie bar until you get the car balance figured out. You may also be running a converter that is too tight [ not enough stall speed]. Basic idea is your stall should be 1500 rpm below your shift point. You can try changing your slick air pressures. With my Goodyear 31x12x15 , I lower the pressure to 5 1/2 to 5 3/4 when I looking for more tire speed, and raise it to 6 1/2 looking for more bite. Call M&H to get some suggestions on tire pressures.
My thought is you might be dead-hooking your tires. Looser converter hits the tires softer, lower tire presures or allot high presures [ 7+ lbs] should allow more tire spin to keep your motor in the RPM range your motor is making good power.
Without using a wheelie bar you have a good chance of sending me your front wheels to fix.
BTW I know FED running in the 7.60 class running on pure alky, some with only 355 ci SBC injected.
Feel free to call me, 805-444-4489
Jon
Scottmech:
Jon....thanks for the advise.
I agree with you on some points, but respectfully disagree on others (which might be due to my lack of experience...lol)
Ballast...agree and all ready have some for the front axle
Converter...agree but will probably have to wait for next season
Contact M/H....agree and all ready have
Wheelie bar....disagree. Is there a chance of it doing a wheel stand?? Depends on how the car is set up to run. Not going to go into detail as to what my set up is, but results from the second time I took the car out proved that the set up is working. 60 ft times weren't anything to write home about, but quick 60 times don't win races..... consistent 60 ft times do. And as I said before, I'd rather be slower and look more period correct than push the 60 ft limits of the car and have a bar hanging off the back of my car. May not be the popular choice...but it's mine.
Besides....if the car does wheelie and wheels get bent...you'll make some money off me....lol
I'm aware there are faster SBC's in FED's running alky, but that really has nothing to do with my car. They may be running 7.60's, but they aren't doing it on my budget....lol. Fact is my current motor is only capable of 410-425 hp in current config (not gonna tear down a perfectly reliable, proven motor just to go faster). With everything perfect (right converter, best launch, good weather, maybe even a better cam since the blower cam is still in it, etc...)......the car should run 8.5. But most times conditions aren't perfect, so that's why i'm shooting for 9.0 index with the current combination. Will easily be able to do that even in June at Bowling Green with 95 deg weather and REALLY bad air. lol
Have no illusions about the car setting the world on fire. I know it won't. Just wanted to build something that had the looks of a mid 60's FED (which my car doesn't just look like one....it actually IS one) but easy to maintain/operate, be reliable and reasonably consistent and take me a few rounds (which would be a step up from my last car...lol). So far, I'm right on target.
Again, I appreciate the help.
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