Gear ratios

[Paul Deslandes]

When my '95 Vx engined car was first supplied, it came with the standard Type 9 box and ratios. As is well known, these are not even really suitable for the road, never mind competition with an excruciatingly low first and pretty useless second.

 

Once I started competing in hillclimbs and sprints, the only serious option, apart from going for a modified first gear, was to get a Quaife straight cut 'pro' gear set. I chose the longest first, 2.04, on offer and whilst this gives a screaming 60mph + in first, it makes the car difficult to get off the line and is not easy in traffic. The straight cut is also awfully noisy and on a long road trip really gets to you, even with headsets on.

 

This year I decided to build an SPC semi-helical with a shorter first to make launch/road driving easier and quieter. The box is certainly quieter and road driving, if not a treat, is much easier with less clutch work in traffic. The problem is that first and second ratios are too low for competition. I opted for the 0.82 5th for motorway cruising.

 

I plan to have a conversation with Steve at SPC to see if he would consider a better set of ratios for his semi helical gear set but I'm interested to know what ratios others use for race/speed events.

 

The engine is 245bhp with 195lbft of torque of which there is plenty to pull from under 3000rpm up to 7500 plus. I've no need or interest in a 6-speed.

 

My favoured option at the moment is to go back to the Quaife, put up with the noise, and fit the 2.2 first and 1.69 second. I Have a 4.11 diff.

 

Paul

[johnnyseven]

Can't help you with the gear ratios Paul--- but if you plan a conversation with Steve you had better cancell any other things you had planed for the following hour or two-- lol

[OliverSedlacek]

The BGH Type 9 box comes with an 0.89:1 5th. I'm very happy with the ratios in it the price is very good (£750 from memory).

[Eugene]

My BGH Type 9 Ratios: 2.920 1.860 1.295 1.000 0.850

 

With a 3.89 final

 

I find them just about perfect...

 

 

Edited by - Eugene on 10 Jun 2013 07:54:50

[kenny.]

Favourite box I've ever had Paul was also a Quaiffe pro with 2.04 first. Only bettered by the 6 speed which you don't fancy ...........I didn't fancy it with a VX but it's perfect.

 

2.04 for sprinting was great if only for the lack of needing low down gear changes

 

Edited to add, I loved the sound of the x/cut gears too, I miss it with the 6 speed.

 

With your 4.11 diff even a 2.04 won't seem too tall would it?...think I ran a 3.6 with mine.

 

 

 

 

Edited by - kenny. on 9 Jun 2013 22:30:32

[LesG]

I'm also running a Type 9 with long first and 0.87 5th, 3.92 final drive and 1.6 K Series.

Although 1st gear is now perfectly fine, I keep wishing I had a taller 2nd gear for sprinting with, as I often find my car either screaming in 2nd, or 'bogging' a bit in 3rd.

A CC 6 speed may even be the answer........

[Birkin S3 ZA.]

I fitted a TranX box with 2,48 1,69 1,27 1,00 0,90 diff is 3,89 same power and revs as your motor.

Work well on track or road, 5th gear is the noisy one the rest just adds to the music. 😬

[oilyhands]

Had a BGH rocket 5 with 0.91 5th for 8 yrs in my seven, utterly brilliant. Combined with a 3.9 diff and 15 inch rims, the gearing was nigh on perfect.

 

Oily

[rgrigsby]

I'm running a BGH 5 speed with the heavy duty gearset with the following ratios

 

2.75

1.75

1.26

1.0

0.86

 

This is with a 3.92 diff, my engine is around 250bhp and 210lbft but only revs to 7500. They seem to work pretty well on my car.

 

Cheers

Rob

[7 wonders of the world]

I ran a both 2.48 and 2.38 thro to .82 on my 254bhp Duratec pretty perfect all usable and you can drop into first at around 35mph no worries coupled with a 3.92 LSD. These were Tran X SC sets but would uses Steves SPC set next time - much better in many design ways than the Tran X or Quaife - give Steve a call and he will talk you thro it unless your in the area then pop in - make sure you have a couple of hours to spare though.

 

Forget any of the BGH 2.75 2.93 first they are way out for a car weighing 500kg.

[BBL]

Quoting rgrigsby: 

I'm running a BGH 5 speed with the heavy duty gearset with the following ratios

 

2.75

1.75

1.26

1.0

0.86

 

This is with a 3.92 diff, my engine is around 250bhp and 210lbft but only revs to 7500. They seem to work pretty well on my car.

I have the same HD BGH, with same ratios, also with 3.92 diff, with similar power levels (mine is a bit less, likely due to U.S. gas having less 'oomph' than U.K. petrol). Seems to work well enough for me on my car.

 

edit -- Agree that a 1st less than 2.5 would be desirable.

 

Edited by - BBL on 11 Jun 2013 22:04:08

[Shaun_E]

I suggest getting a copy of gearcalc and plugging your ratios into that. Look at what revs each up change will drop you to and then look at where that is on your power plot. Everyone said to me that I should get a 5 speed to go with my "torquey" (ha ha) Duratec but each gear change would have dropped me half way down the curve and well out of the power band. My 6 speed is much better and keeps the car on the boil - it also means you are less likely to be caught between gears for a particular corner. I love the 6 speed and with a 3.92 diff it works very well on the hills. I run out of revs on the big circuits but as we do so few of them it isn't a real issue. Top speed is 129mph @ 8500 rpm.

[LesG]

I've dug out the invoice for the BGH E3 HD gearkit I bought, and the ratios appear to be; 2.92, 1.86, 1.295, 1.00, 0.87.

I'm a little confused as 'E3' doesn't appear on their options list now, but I think I'll ring them and have a chat about swapping ratios for my 1.6K SS. This set was originally bought for the car when I rebuilt it as Xflow.