FrontEngineDragsters.Org Forum
Drag Racing Discussions => Front Engine Dragsters => Topic started by: Flint78 on March 14, 2017, 07:12:43 AM
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Hi guys, I have never driven a FED, sat in Altered few times that's it. My previous experience was only with door slammers and pro-street.
So as I was sitting in altered dragster with my legs over the rearend, I started to wonder. What options for driver security against explosion of transmission, shaft coupler or third member. Do you use some kind of special rear end cover, or any kind of scatter shield ? A friend of mine had a kevlar cover over TH400 in his dragster. When the tranny exploded, parts flew all over the place, leaving huge hole in the door. Fortunately my friend got lucky and only got out with torn safety pants.
What options there are in order to minimise the risk in this day and age of safety equipment.
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A NHRA or IHRA rule book would be a good place to help answer your questions. There are so many items and issues to cover a simple reply wouldn't get it covered.
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True, I will get to that, I was thinking more in a way of rear end cover selection, kinds of scatter shields etc
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Rear ends simply do not break and explode any more, If they do their likely cause is from cheapness and stupidity.
Good 3rd cases are widely available thru the aftermarket. A stock Ford non nodular case from a passenger car is so weak that the helix of the pinion gear will push and break the pinion carrier out of it.
spools are used in dragsters instead of open diffs and do not explode
Better gear material is used and are heat treated softer than street gears for flex during impact. Gears do break on occasion, but thats usually at the hit when speeds are slow and just knock the teeth off, nothing comes out.
Back in the early days, the junkyards were the main source of parts--- there was no aftermarket unless you went to a Halibrand QC, and those were more likely to explode and in you lap. welding spider-gears weakened the diff that it would break or just the diff would break on its own. Street gears are extra hard so they could last 100,000 miles, Race gears dont need that long of service. The biggest fear was when the rear end would lock up at speed and rip out of the frame into the drivers lap and tearing him up. With SFI specs requiring 4 per side 7/16" bolts and an anti rotation plate/mount. The use of a quality aftermarket case and spool, proper gear material for the application, Its somthing that is no longer a concern for the racer and its only brought up by those in the spectator stands. A guy once asked me if the rear end got hot sitting over it? I replied---7 seconds is not enough time for it heat up
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Thanks for that info, helps a lot. I live in Poland - no dragsters here at all. I will be reading and asking you guys a lot here, for a year or 2 - until I finish my new house and finally have a decent garage to start FED project for real. ;D
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I get that question about 20 times a day at the track so I just started saying
"You can't blow them off if you ain't got'em"
that usually settles it
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reply yea its dangerous but that makes it cool.
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i was surprised at how many stock rearend housings guys where using. some were gusseted across the pumpkin. they had aftermarket third members but the housing itself looked stock to me.
dean
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Dean,
in the early 70's my Don Long top fuel car had a narrowed but otherwise stock 8 3/4 Mopar housing with a factory iron third member. When it was built it had a Mickey Thompson mag third member but before it got to the strip it had the stock unit fitted.
In most of my current builds I use the Strange H1110 housing without a brace and have never had any issues (even in NT/F applications)
Roo
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i was surprised at how many stock rearend housings guys where using. some were gusseted across the pumpkin. they had aftermarket third members but the housing itself looked stock to me.
dean
I have a customer who's car I built in 2003 that was supposed to be a mild fun car. Of course it's morphed into a blown big block for the 7.0 class. Used a new stock type 9" housing and it's still in the car to this day, no back brace. Don't forget that some of the fore/aft flex in the housing is mitigated somewhat by the narrowness of the housing, axle size, and maybe even the anti rotation device. Would I have preferred to use the housing that Roo uses? You bet I would, and it's all I use now unless a customer requests something different.
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I cut the back off another 9 inch and welded that "cap" on the back of my housing
If I were to do it again I would skip that and save the weight
Our cars don't have enough weight to break rears
A door car is a whole different animal
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The availability of an aftermarket housing is a boon to builders, Finding housings in the wrecking yards, cutting them down and cleaning them for use, took soooo much time and labor that would be hard to get payed for. Now you just order up a clean new unit made with even better material
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mine has the mitler bros housing and strange ultra pro third member. just surprised me to see so many stock housings in a lot of the feds. i figured it would be commonplace in some of the faster cars to have aftermarket housings. i get that some of these feds been around a long time and people do not upgrade for whatever reason. i also understand even in 7.0 a fed is prob making 1200 hp to run the number comfortably and stock housing might be able to handle that for a while. would you think the third member would fail first before the housing? this is assuming the housing mounting is up to nhra spec as noted earlier.
dean
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The (new) stock housings offer more room for the drivers legs whereas the fabbed sheetmetal housings are bulkier. Running a stock Ford 9" housing with CM tubes and no backbrace, installed for over 20+ years, ZERO problems. But it helps knowing what you are doing
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Dean,
Bruce is right on the money regarding the amount of room that the fabricated housings take up. Some manufacturers (Moser is one) make the housing so that it has a symmetrical appearance from the rear and that results in extra material outboard of the chunk on the right side. In the case of a handbrake car especially, this is not a good thing. Some of this problem is negated if you have a "high chair" car like some of the newer NT/F entries but we don't like them anyway and prefer a true nostalgia look. :)
The other advantage of the Strange H1110 is that its design means that the axle tubes are very well supported due to the length of the welds that secure the tubes. Most of the others simply weld the housing to the tube at the end of the housing taper and to an internal bulkhead
(https://www.strangeengineering.net/wp-content/uploads/2013/11/Center-Hsg-Front-500x500.jpg)
Roo
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Thanks for the info guys, appreciate any info regarding practical info. Looks like I need to slim down to fit into that FED anyway :) Kinda at 240 lbs right now.
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Every 50 lbs is a tenth in a FED
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Why is 50 a .10 in fed and 100 is .10 in most other styles of drag cars? So the 50 extra my car weighs cost me a .10 instead of .05,now I'm pissed.Got to buy me some new drill bits and end mills.LMAO
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Dean,
Bruce is right on the money regarding the amount of room that the fabricated housings take up. Some manufacturers (Moser is one) make the housing so that it has a symmetrical appearance from the rear and that results in extra material outboard of the chunk on the right side. In the case of a handbrake car especially, this is not a good thing. Some of this problem is negated if you have a "high chair" car like some of the newer NT/F entries but we don't like them anyway and prefer a true nostalgia look. :)
The other advantage of the Strange H1110 is that its design means that the axle tubes are very well supported due to the length of the welds that secure the tubes. Most of the others simply weld the housing to the tube at the end of the housing taper and to an internal bulkhead
Roo
interesting, had no idea that was available. mines a high chair setup modern style chassis. we talked about height but idea was to look over blower instead of walls. at least thats way i understand it. i can see on non-blown carb or injected deal having seat lower. my buddy's is real low, i cant even get out of the sucker haha. im gonna use hand brake, its a tight fit in these things anyways. i dont know any difference so it will be perfect whatever it is haha.