Changing Gears

[cobra 53]

An other help to make a resolution.

http://www.5speedtransmission.com/calculators.html

Read the sections:

- Startingline Ratio
- Calculate the distance travelled in 1st gear

Rico

[JBCOBRA]

un-useable ratios in an SPF

[JBCOBRA]

You are just not getting the concept....
Traction is Totally useless....
Maybe you guys use your cars for Parades or something?

Originally Posted by mpanten

40 Mph with 4.10's at 6500 seems good to me. How is over 40mph in 1st useless?

[rgnbull1227]

Being that I was looking for a extra accel, I've talked to a few highly respected SPF engine builders/dealers. Most of which are on this site. ALL advised on going to 4.10 gears rather than heads, cam, etc on my engine/tranny combo. So thats where I have been getting this advise from and not just pulling these things out of the air and throwing crap against the wall. NEVER track the car. Street car and want some better performance. Thats what I was looking for. And NO......NO PARADES for me.

[mpanten]

Originally Posted by JBCOBRA

You are just not getting the concept....
Traction is Totally useless....
Maybe you guys use your cars for Parades or something?

Parade car? No. I get what you are saying I just know for a fact that your wrong. I run drag radials and have no problems hooking up. Get rid of the BFG or Eagle Gt's and join the word of useable horsepower.

[SPF1061]

4:10s will be beyond useless IMHO. Run all the gear calculators you want.
They will predict your cruising speed/rpm with some accuracy. They cannot predict traction, or in this case, lack thereof. There is not a street legal tire made that will come close to gripping in first or second in a 500+hp / 2400lb / IRS / 4:10 geared car. I am running an SPF with Roush 427R, 3:27 gears with Torsen positraction, TKO600, Avons on the street and BFG drag radials at the strip (only because they are cheaper than Avons-they don't grip any better). I can smoke the tires off the car at anything over a 2000 rpm roll in first gear. You will not be able to touch the accelerator in first without instantly hitting the rev limiter. Sounds like fun. If anybody is telling you otherwise they are giving you BAD information.

[blykins]

To each their own.

Big gears work for me and this guy doesn't have a 500+ hp engine with gobs of torque.

If you want something that will hook up at WOT in any gear, put a 4 cylinder in it.

And for the record, no, I'm not giving BAD information.

[SPF1061]

RGNBull 1227 -
Looking back over the posts I don't see where you said or anyone asked - what engine are you running? Maybe it's there and I missed it? Just curious. If you are running a bone stock 351 or less, perhaps moving towards lower gearing would give you some advantage, though 4:10 seems excessive even at that.

[SPF1061]

Originally Posted by blykins

To each their own.

Big gears work for me and this guy doesn't have a 500+ hp engine with gobs of torque.

If you want something that will hook up at WOT in any gear, put a 4 cylinder in it.

And for the record, no, I'm not giving BAD information.

Sorry, I did not mean to be insulting. I'll get off my high horse now. It occurred to me that I knew nothing of his motor and posted that question before I read your response. I was speaking from my own personal experience. From where I sit, 4:10s on an adequately powered Cobra seems like pouring fuel on a fire. There is no question in my mind that your experience far exceeds mine. Whatever works.

[blykins]

No problemo.

I believe when we talked he had a lower hp 331...maybe 400-ish hp if I remember correctly. He was wanting to try to get up to the 500hp range, but that would make for a very high strung engine that probably wouldn't be that street friendly.

Going from a 3.46 to a 4.10 would net a pretty dramatic seat of the pants difference. No, you may not be able to flat-foot it in 1st gear, but I think one of the learning curves to owning a Cobra with more than 300 hp is learning to pedal a little bit.

It's a lot cheaper than buying a new engine too....hahaha

[rgnbull1227]

Yes. Engine is a Performance Engineering built 331 Stroker. 415hp and 410 Trq. Ive had big HP cars previosuly(600hp Lambo, 500+HP BMW, 450HP Lotus, ZR1, etc.) plus lots of track time in cars/race cars so Im pretty good with the right foot. Everyone said even with 400+hp this is a fast car. Now that I have it....looking for more. The problem is I love the drive-ability of this engine. Its a great driver and it is definitely fast, but looking for more. I am looking at building a 427 Stroker with 500+ hp as well so the gears may be going back to a taller gear once a new engine is in place.

[frdfver]

72-86 mph @2500-3000 rpm and 187mph @6500 seems good to me for a street driven car. Seems like drag racers will always go with the lowest rear ratio that will yield them the rpm and speed at the end...Then make it hook up. Thats if your only looking for accel from point a to b. Always take into account the rpm the engine likes also.

[mpanten]

Originally Posted by rgnbull1227

Yes. Engine is a Performance Engineering built 331 Stroker. 415hp and 410 Trq. Ive had big HP cars previosuly(600hp Lambo, 500+HP BMW, 450HP Lotus, ZR1, etc.) plus lots of track time in cars/race cars so Im pretty good with the right foot. Everyone said even with 400+hp this is a fast car. Now that I have it....looking for more. The problem is I love the drive-ability of this engine. Its a great driver and it is definitely fast, but looking for more. I am looking at building a 427 Stroker with 500+ hp as well so the gears may be going back to a taller gear once a new engine is in place.

Im running a stroker 427 with about 550 hp. The 3.73 are fine and so would anything up through 4.10. I dont know what to tell the people who say it would be useless other than your welcome to come for a ride with me and I can show you how useless they actually are.

[JBCOBRA]

This also makes a big difference:
Model (ft/lb) input
spline output
spline 1st 2nd 3rd 4th 5th
TKO 500 500 10 31 3.27 1.97 1.34 1.00 .68
TKO 600 600 26 31 2.87 1.89 1.28 1.00 .82
TKO 600 600 26 31 2.87 1.89 1.28 1.00 .64

[mdross1]

All any of us can do is make suggestions since we are all different and have different needs for our cars.
Once my car was on the road and I trusted that everything was 100% then started the dail-in.First was the handling had it scaled,then the brakes 12" Willwoods all around took care of that.Finally the gearing a TKO,and a 3:70 cog made my car everything I had hoped it would be and then some.
Keep toying with the idea of a stroker big block since I have a spare 460 but the motor in the car is very predictable.You guys here with the really big guns arent making it any easier.

[itstock]

Originally Posted by mpanten

Im running a stroker 427 with about 550 hp. The 3.73 are fine and so would anything up through 4.10. I dont know what to tell the people who say it would be useless other than your welcome to come for a ride with me and I can show you how useless they actually are.

What drag radials are you running, and what prepped streets do you drive on?

Or are you talking about tracking the car and how it comes out of turns in 2nd gear or greater?

I've run drag radials on plenty of cars. I have used my car on the streets many times. I've been on the track a bunch of times. 450+rwtq starting at 1800rpms is going to light up the tires in 1st gear on the street, and at an unprepped track.

I am trying to grasp how you are able to do it, but I just can't come up with a logical conclusion in a car that has 1300#'s over the rear tires.

In a a car with substantially less power, that won't have the traction problem to this extent, I understand the reasoning for a lower gear. It's a quick way to save money and get the desired results. But there are two different discussions going on, one with you and one with the OP, rgnbull1227. Spinning tires is useless IMO. Your opinion on what the definition of useless is obviously differs.

[D-CEL]

A 4:10 gear is a great gear for a Cobra
I have run them for years and love them.
If you haven’t run them in a Cobra how can you offer a valid opinion? A wild-a$$ guess adds no value to the discussion.
Here is another recent thread
Rear end gear question
You girly-men are STILL good for a laugh! It doesn’t matter what gear you run if you have crappy tires. Goodyear GTIIs are worthless, greasy, spinning $hit-piles even with a 2.90 gear and 450hp. Put a good sticky tire on the car and you will realize how quickly that you can use a lot more gear.
Rgnbull,
Are you just collecting parts to have it done? Or are you going to do it yourself?


JASON

[itstock]

Originally Posted by D-CEL

A 4:10 gear is a great gear for a Cobra
I have run them for years and love them.
If you haven’t run them in a Cobra how can you offer a valid opinion? A wild-a$$ guess adds no value to the discussion.
Here is another recent thread
Rear end gear question
You girly-men are STILL good for a laugh! It doesn’t matter what gear you run if you have crappy tires. Goodyear GTIIs are worthless, greasy, spinning $hit-piles even with a 2.90 gear and 450hp. Put a good sticky tire on the car and you will realize how quickly that you can use a lot more gear.
Rgnbull,
Are you just collecting parts to have it done? Or are you going to do it yourself?


JASON

Go post a video of you driving around punching the gas in first gear with 450rwtq , and how you don't spin the tires. "I'll believe it when I see it".

And we can comment because we have decent tires, and spin the tires with a much higher gear. And we have driven other cars with drag radials...and 4.10's, or whatever other combo.

The reality is that a 2600# car with one of the many lower rpm 427 SBF's will be useless in first gear with 4.10's.

ETA: I can't even comprehend how this is up for debate. If you want to say that you like 4.10's because you have more fun spinning, that's perfectly fine. But again, I call that useless. Obviously opinions and definitions of useless differ. However, it sounds like you are indicating that 4.10's are not useless by traction standards which goes against reality (talking about with any bit of power).

[mpanten]

Originally Posted by itstock

What drag radials are you running, and what prepped streets do you drive on?

Or are you talking about tracking the car and how it comes out of turns in 2nd gear or greater?

I've run drag radials on plenty of cars. I have used my car on the streets many times. I've been on the track a bunch of times. 450+rwtq starting at 1800rpms is going to light up the tires in 1st gear on the street, and at an unprepped track.

I am trying to grasp how you are able to do it, but I just can't come up with a logical conclusion in a car that has 1300#'s over the rear tires.

In a a car with substantially less power, that won't have the traction problem to this extent, I understand the reasoning for a lower gear. It's a quick way to save money and get the desired results. But there are two different discussions going on, one with you and one with the OP, rgnbull1227. Spinning tires is useless IMO. Your opinion on what the definition of useless is obviously differs.

Im running Mickey Thompsons. I dont know what to tell you. I come off Idle and nail it. Others with similar set ups do the same thing. Greg Schroeder is a prime example. If useless in your opinon means dumping the clutch at 2k or more and not spinning than I guess you are correct. But to say you will have no traction and that the car will be undriveable is 100% false. How do I know this? Beacuse I do it!

[itstock]

Originally Posted by mpanten

Im running Mickey Thompsons. I dont know what to tell you. I come off Idle and nail it. Others with similar set ups do the same thing. Greg Schroeder is a prime example. If useless in your opinon means dumping the clutch at 2k or more and not spinning than I guess you are correct. But to say you will have no traction and that the car will be undriveable is 100% false. How do I know this? Beacuse I do it!

Greg Schroeder does it on a prepped track with ET STREETS. Have you tried driving around on aired up ET streets...on the street with no heat? They suck. There is NO traction with them. Heated and aired down, great. Otherwise, no. And don't even attempt any turning on them.

We are not saying the car will be "undriveable'. We ARE saying that any gas given in first gear is a waste. You are really sitting here telling me that with 450rwtq (and it's funny to think that 450rwtq isn't even that much), in your go kart of a car, you can come off idle on the street (or from a roll in 1st), nail it, and not spin?

I just, well, I really just don't know what to say or how to even respond to you. Congrats I guess. It's really an amazing accomplishment.