1/4 mile times

[greg schroeder]

Originally Posted by ItBites

Greg, Nice times, glad it continued to run faster as the day went on.

Jeffko, Straight axle does dominate drag racing (primarily due to KISS design and ruggedness), but I know of many IRS cars in the 9s, so until we're talking about 9s, I do not think there is the difference in performance (maybe breakage) that is purported. When our cars are running 9s, then we can have the IRS is no good for drags debate...

I suppose there are many things to consider as well as ways to put things into perspective.

As to drive line endurance I have most always started from a bit above idle to be easy on the drive line, but once tried to launch from about 3000 rpm with the Superformance half shafts. The inner splines, driver side shattered with in the differential. I picked up stronger complete half shaft assemblies from The Drive Shaft Shop, but don't intend to launch the car again. Well, I'll try not to. The Drive Shaft Shop did say the new parts would stay together none the less.

The trap speed and DA (density altitude) pretty much tells the story of what a car could do relative to sea level if it hooked and the drive line didn't blow apart on hard launch. In my view I don't really want to thrash the car to get a time, so I just theoretically apply a bunch of coulda what ifs. You won't break parts that way. Theoretically same DA(2100-2200ft) and HP for my pass above with all together drive line hard launch would be a 10.55 if a drag racing calculatorwas used to estimate working off trap speed HP. If the time and speed is evaluated in perspective to sea level corrected It's a 10.28 @132 mph.

Time and speed corrected to sea level, and with the addition of 42 HP and perfect hard launch run(wet shot NOS and solid engine mounts tempting to install), the car has potential for a 9.99 @ 136.5 . The problem there's always another guy's car that's faster.

I know, I think way too much and have too many dreams.

[Jerry Clayton]

A reason the solid axle is better for drag racing is that you can use the bars to transfer weight to the rear--IRS does reduce unsprung weight for road racing , but will not necessarily be faster that a well setup solid axle car--the IRS set up is necessary with rear or mid engine cars. IRS probably rides nicer on the road.

My choice is a three link system, but you can get torgue steer with the front wheels are in the air

Jerry

[jeffko]

Itbites, I did not say the IRS was no good for drag racing. I did and do claim it is not as good as a solid axle for drag racing, but is a better choice for versatility.

[Fred Z]

Greg.....while reading your times........it occurred to me......for all the hoopla on Vetts vs Cobras.......in another thread.....maybe the orig Cobra would have problems........by my contention is that these replicas would smoke the Cheveys.......but of course , that is another topic............
nice runs...............

fred z..................

[fastmax1]

Some really good times posted. These cars dont seem to be the best 1/4 milers but I am planning on beating mine at the strip anyway. The car is a BDR (#451) and is a week or two away from delivery. The motor is a 418 stroker from Proformance Unlimited and was designed for a 250 shot of nitrous. We are hoping for 700-750 at the crank with the bottle. Custom Cars supplied a modified drivetrain to take the punishment. I look forward to posting some times myself, but realistically I probably will not be at the track (Moroso) until mid January.

[jeffko]

Max, please explain what the modified drivetrain consists of.

[CHRIS DAMSCH]

Jeff, Jeff, Jeff. Save all that money on your improving your car and invest in some driving lessons from me....LOL All that power and still 12 sec. time slips.

Sorry, I couldn't resist.

You'll get in the 11's this year for sure with the new rear end and carb.

[jeffko]

All I need from you are your tires. How about we swap and see what happens?

[BOURRET]

I learned a lot from this thread. I will change my tyres.

[Wolfie]

Sure Jeff you can have Chris's tires now that I'm done with them!!! Didn't you see what they did to my car? They broke my halfshaft!!!! what the
%&#@. It sure felt great when it happened, I'm sure that I would have run in the 11's had I not busted the shaft! There in my garage come and pick them up, Merry Xmas.

[thunder1]

I have own a backdraft for almost 3 years and have not heared of a backdraft breaking a halfshaft,
enjoying this car more everyday ed

[Jerry Clayton]

you won't break them with a 302

Jerry

[jeffko]

Thunder, that Wolfie character that broke his half-shaft is driving an SPF. I have never heard of anyone breaking a half-shaft in a BDR either. However, I have heard of a BDR guy that broke the output shaft of an open diff though. At the time the car had just left the London burnouts and was in front of the Hampton Inn preparing for a spirited drive thru Hocking Hills. (With the exception of my 2 sons, why is it always a woman at the root of anything bad happening to me? That could be the most profound rhetorical question ever posed, at least for me!) Anyway, with 2600 miles on the odometer and countless beatings being twisted into it by a TKO and everything in front of it, I was not surprised...pissed, but not surprised.





Santa/Wolfie, thanks for the offer, but I must have tires that slip at least a little. Which brings me to this question. How come you break your car the first time with drag radials, but Chris has been using them even as street tires for years. You guys have the same cars, diffs, half-shafts, driveshafts, trans.....ah ha I think I have answered my own question.

[CHRIS DAMSCH]

Jeff, I think the only reason I haven't broken a halfshaft is because I don't ever leave the line like a raving lunatic (aka Wolfie). I ease into it then push it to the floor.

Maybe I should give Wolfie those driving lessons for Christmas? Hmmmm, that would bring the family stock back up a little.

Chris (chasing the dream of 10's)

[Wolfie]

Chris (chasing the dream of 10's)

Chris you better keep chasing cars and give up on the "10's",,,,, have you seen Bo Derick latley?!!!!!!

[greg schroeder]

I broke my inner splines on driver side within the differential on my Superformance Ford 8.8 rear end. All it took to eliminate the part was drag radials and one 3000 rpm start. All of my other starts before and after the incident have been near idle rpm. The half shaft chunks that were left over looked to be heat treated cast metal with mini hallow spots in the structure here and there in the middle.

I bought a new set of half shafts from DRIVESHAFTS SHOP: Stock, Performance Drive Shafts, Aluminum Drive Shaft, Racing Axles that are said to be stronger. Of course the little broken bits and chunks filled the differential and rear end too. I put in a Detroit Trutrac rear end to replace the other.

[fastmax1]

Jeffko, sorry for the delayed response... finally got a little vacation. The tranny and rear end have both been modified... but honestly, I do not know the exact modifications. I will be receiving a build sheet from both of the shops that did the work. The tranny is a t56 and all I know is that the input and output shafts have been replaced, the gears cryo-treated, shift forks replaced and different bearings. The rear end is a m3 and some modification was done to the crushable cone and again the gears were cryo'd and the bearings replaced. I wish I knew more. The car drives great right nowThe nitrous will be going in next week and I am hoping to be completed with that by 1/12. Anyway, I should have some dyno numbers to post by theen and I will PM specifics on the drivetrain mods if you like. I plan to be at Moroso sometime in the next couple weeks to try a couple runs and hopefully have some decent times to post.

[jeffko]

Cool Max, I would indeed like to see what your setup is and good luck at the track. What rear tires are you going to use? Keep us posted.

[fastmax1]

I could use a little help with the tire selection. The car currently has 315/35/17 Nitto DR's. Obviously too low a profile for a good launch. I picked up some 15x11 rims for the rear and was considering Goodyear slicks or maybe the MT's which I have heard a lot of good things about (if you are like me and you consider broken half-shafts a good thing).

Have any suggestions?

[jeffko]

I am going for the MT Streets myself. I can't trailer the car to the track so they are the next best thing.