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What good is First Gear?
OK....I'm sure you'll all laugh at me, but having my Cobra on the road since 1996, I still havn't figured out how to drag from a standing start. Most of my fun is from about 2000 rpm in second and shifting into third. If I try from a stop in first, the engine seems to rev before I get any speed (of course) and I feel I've wasted my time. Perhaps I ought to start in 2nd and drop the clutch from about 3000 rpm?
It feels like first is geared too low, but yet, when I drive normally, first almost seems to high when I leave from a stoplight. I am using a 3.07 differential with a Richmond Gear 5-speed (standard 1st gear) and a 428 FE. So...any advice from you dragstrip guys? Thank-you. |
what tires are you running?
Dwight |
295-50 BF Goodrich TAs. Street tires. And speaking of that, I have to really put up the rpms and pop the clutch to squeal. Lack of power? Nope!!! Car just goes faster and faster the more I give it gas, which really, is what it should do at a 50:50 weight distribution.
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If I remember correctly the Richmond transmission 5th gear is 1:1, so you have to do a lot of shifting. Others have started in second for a drag run. I remember Keith Craft ran in the run-n -gun several years ago with a very high hp big block and had to start in 2nd to get his best times (low 10's) with 4th gear being 1:1, but burned out his clutch. The Richmond 5 spd to get to 1:1 compounds the problem for drag racing.
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Your tires are your biggest problem. BFGs are worthless except for casual driving.
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To tell you the truth, my main problem with 1st is that I can't tell what''s going on. If the tires are spinning, I can't tell. If I over-rev it, I can't tell that either. It's like I only have a tiny fraction of a second before I decide that 2nd might be a better place to be. PLus letting off the gas a bit to shift from 1st to second creates a bit of a hesitation due to a tiny bit of engine braking...which I guess is my technique...so there's quite a lurch...read "delay" when I make the shift.
I wold think I should hit 30 mph or so in first before I shift, but it seems like I only do about 30 feet before I decide "this isn't good" for the engine/car. I only drive on the street, so track tires are out. At the time, all I could find in the correct sizes were the BFGs. I think Michelin did make them, but discontinued that rear size before I was ready to install any tires. Summit has street tires, but I was unfamiliar with the brand names and/or reputation of the tires they had. I really think my tires arn't the main issue, it's the way I drive that could use improvement. On the other hand, I do limit myself to about 1/2 throttle during 2nd gear and 3rd gear runs as I am worried about losing traction. |
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As was mentioned, BFG TAs suck on a Cobra (in terms of performance or traction). Don't underestimate the importance of putting some good "meats" on the car. In terms of your driving, perhaps you should ease up a bit on dumping the clutch at 3,000 rpms and your launches would improve;). Take a look at Greg Schroeder's (a member of the forum) quarter mile pass in his small-block SPF (there's a link from his profile attached below). You'll notice he runs in the 10s and is not dumping the clutch at launch. http://www.youtube.com/watch?v=XmDd14eITU0 Good luck. |
Nice video. Thank-you. My favourite is this one:
http://www.youtube.com/watch?v=GJPwxLZGzlM That 3000 dump the clutch thing was jus a thought if I wanted to start in second. Clutch work aside, I may do some trials while already in first and just off-idle at around 1000 rpm and see what happens. LOL....nobody wants to admit they can't drive, but here I am...."My name is John and I can't handle 1st gear!" Normal driving, I'm fine. Way back when, I used to lose Camaro's quite easily on windy country roads with my 74 Datsun 710. Only mod was wider tires (Michelins). I don't play those games any more. Common sense has prevailed. |
Argess,
I'm not a drag racer, so I can't offer much in the way of launch/shift technique. But my car has about the same transmission/differential setup as yours. With my rev limiter set to 6,000 first gear is good to about 50 MPH and each subequent gear is good for another 25 MPH. Full throttle on street tires will cause the tires to break loose in 1st, 2nd and 3rd gears. So for a spirited launch, I can't give it full throttle at the beginning. I find it hard to modulate the throttle well enough to give maximum acceleration without the tires breaking loose in 1st gear. So I usually shift from 1st at about 3,500-4,000 RPM. That puts me in 2nd at about 2,500 RPM (where my torque band starts to get strong) and I can modulate the power much better in 2nd. As I said before, these are not race techniques and I have no idea if they yield the quickest track times. |
I run the M/T 315/35/17 ET Street Drag Radials and first gear's is VERY usefull (325 to 1 rear gear, with TKO 600). When I drop the rear tire pressure to about 12psi and do a healthy burnt out I can hang the front tires around 6" in the air out of the hole.
Surprisingly, the shorter sidewalls work very good in the twisties too**) Now rain .... that's a different (scary) story. Dave |
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Thanks Tommy. My enigne likes to make power starting around 2500 (maybe a bit less) as well. I have no rev limiter, so I have to pay close attention. A few weeks ago, I managed the 2nd to 3rd shift around 80 mph. Working backwards through the gear ratios and tire circumference, it appears I over-revved the enigne a bit at about 6600 rpm.
Darned erratic Stewart-Warner tach...even when it's working, it follows with a delay. That's why I went with the speedometer reading. I must do some more trials, as this 1st gear launch thing isn't a common thing I do. I'll keep your data in mind. |
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My M/T S/R radials seem to work well...but I'm no expert. Does anyone use them for drag racing?
Let me know, Bill |
Yeah, Put drag radials on it and your problems are ended.
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I see a lot of posts here about tires, but I'm still not sure that's the problem. Here's a similiar scenario. I have a 99 F250SD with a 5-speed manual transmission. I always start in second gear unless I am towing a load or stopped on a very steep hill. Under normal starting from a stop, if I use first, the revs come up too quickly and the shift to second is not smooth. It's more like I can't make the shift to second without a major hesitation and lurch.
Oh well....can't do any trials today...am in the middle of a visitor.....Hurricane Bill !!! Or maybe I could find a road in the right direction and drive into the wind to slow things down for evaluation?.......chuckle. |
Your rear end
"I am using a 3.07 differential with a Richmond Gear 5-speed (standard 1st gear) and a 428 FE.
The 3.07 is more of a highway gear ( you must get great milage ) Tha's why your first gear is not acting "normal". If you are going to Race or lite up the tires for those days you showing off start out in 2nd and rev. However if you want more performace out of the bottom end you'll have to change your rear to something like 3.70's. Most 3.07 were used for getting gas milage in 6/4 cyl. cars not burning off the line By the way, If your going to Dump your clutch above the 3,000 RPM for 2nd shift lainches . Do not be surprised by the rear end exploding...It cant' handle the tor. |
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Ahhh...I see. I won't do that 3000 dump then..... I suppose I could change the gears in the tranny instead, but that's probably more difficult than the diff.
Yes, on the highway, the milage is great. Around town, it's like Niagra Falls in the carbs. The rear end ratio was recommended by ERA and I did some math on it which made things look good, but you make a very good point. I've been really thinking about this since I made the original post and although my memory isn't great, I really think the problem is more to do with an uncomfortable 1-2 shift than anything else. |
Just how old are the T/As? They can get mighty slick after 10 years...
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