Help needed in gearbox selection (gearfox)

[ossme]

(Warning! Long Post!)

Hi all,

I'm trying to build a daily driven. My current engine choice is an LS3 tuned to produce about 500HP and to rev to about 7000rpms. My second option is to use a stock LS7 given that I can source a cheap one.

My current choice for the gearbox is CIMA / Gearfox T756. They have a paddle shift option which is great! I tried to find more information about CIMA / Gearfox transaxles. I also tried to email the factory but there is no replay tell now. I also want some feedback from Ulitma builders who used these gearboxes.


They have the following options

1st gear 2.875
2st gear 1.773
3st gear 1.267
4st gear 1.000
5st gear 0.833
6st gear 0.711 / .733 (do they have more options ?)
Reverse G. 3.000

Rear-axle ratios available 2.916 - 3.364 - 3.545 - 3.700 - 4.111

When I say a daily driver, I'm speaking about Highway driving most of the time, Highways where 100mph is not only legal but the normal thing. Most of my cruising between my work and my home is done at 70MP/H. I want a gear ratio that gives me a usable 1st gear, a good acceleration and 6th gear for highway cruising. I also would like to do 2 to 4 track days a year. I'm not a gearbox expert. In fact I know only little about car technical stuff in general .

I took a manual zo6 as a starting point. I like the gear ratio both road and track performance are good so I want something similar. From the list above I thought of getting 6th gear to be .711 and the rear axle to be 2.916. This would give me a good cruising speed. But how will it affects the car's acceleration?

Alternatively if there is more options for the 6th gear then I could choose something between .65 and .53 and then choose a bigger rear axle (3.74 to 4.11). This will improve the car's acceleration from 1st to 5th gear and the 6th gear will give me a good highway cruising. I'm I right here or something is missing ? I'm really interested in reading your views about this matter.

I also have lots of questions regarding the CIMA gearbox option:
1- What is the estimated price for the gearbox excluding the shipping, taxes.
2- What is the estimated delivery time? (the box been ready to be shipped)
3- Is the chosen gear box adequate for the engine or should I go with the bigger version (T900)
4- Do they offer and adapter plate to mate the engine and gearbox together or should I try to source one myself? If so then from where can I source one?
6- Regarding the Sequential/Pedal shifting options. Are they fully automated options or would I still need to have a manually operated clutch pedal?
7- Do they offer a Shift indicator for Sequential/pedal shift (one that indicates the current gear) ?
8- Regarding the Pedal Shift option. How does it operate? And do you offer the Pedals or do I have to source those myself?
9- What modifications are needed to the Ultima Chassis? Do I need to modify the mounts? if so can the factory do this for me while they build the chassis?
10- What other things/options you advice me to consider

Sorry for the long post guys! Any information even if small will help.

[craig7l]

10- drop idea of paddle/seq and go for manual.

[lpenn]

On the paddle shift front, they can be a bit of a pain but are good for track days etc. You can keep the gear lever and shift manually. You would need to keep the clutch for manouvering and selecting nuetral. If you want a real gadget, you could look at a fly by wire hand clutch.

[Rusti Evo]

craig7l said:

10- drop idea of paddle/seq and go for manual.

Agreed. I had the option of GT3RS/Oakley seq, NLT etc.etc. Decided on nice simple 5 speed box.

It seems to me that its important to decide at the outset whether the car is to be a design excercise or a practical usable thing that can be driven with reliabilty. I went for simple and reliable(hopefully!!)

[GTRCLIVE]

I have a T906H for sale if your interested its in the Ultima Parts Classified.....

[ossme]

Thank you for your replay guys,

The reason I want to have a paddle shifted car is because I want to remove the shifter and the hand brake from the center. This will allow me to have a better seating position.

I'm not going to drive the car in high traffic or in tight spots. But depending on the sequential system design, parking may be a worry think . I drove a Lamborghini with an E-Gear and the gearbox was not that bad. It had its learning curve but in general I really liked it. You press one pedal to go up and the other to go down. You press both any it will send you straight to natural from any position. The gearbox computer wont fully depress the clutch in slow speeds which helped in parking. You can also put it in automatic but I didn't use it in that mode. In high traffic I used it like a manual. Basically putting the car into natural whenever the car crawls to a stop. A picture of CIMA'S paddle shifting mechanismwhich shows that its simple yet may be affective. I also believe that their normal gear box can be converted to pedals but I'm still not sure about this point.

I have tried to search for more information about CIMA and GearFox and went throughout many websites like ffcobra forums and GT40 forums. I also tried to contact CIMA through their official contact email ([e-mail] ). I found basic information about the gearbox dimension and history. I also found out that the designer has a great mind and poor marketing skills. finally, I found that once you buy this product then you are on your own. little used it, the company won't replay and the kit provider will not support you. But I still don't see the porsche gearboxes as an alternative.

Anyone got another contact to this company or a contact for a reseller ?

GTRClive,

I'm really interested in your offer and will email you for more inquiry. But I really cannot take a decision regarding this point when I lack lots of information. So my decision is on hold, Specially with the amount of investment involved.

[V8Dom]

hi
if you want to remove gear linkage and handbrake from the centre, can you not put a manual gear linkage and handbrake on the outside?? we run right hand gear changes on the right here no problems, not sure if its been done on left hookers but is it not a case of just fitting it on the otherside and redoing the linkage?? and then handbrake behind it, or even a merc foot mechanism for parking brake, offset under the dash...


IMO sounds too expensive and long winded just to move the gear/handbrake otherwise??

Dom

Edited by V8Dom on Wednesday 10th February 10:41

[spatz]

ossme said:

Thank you for your replay guys,

The gearbox computer wont fully depress the clutch in slow speeds which helped in parking.

Probably the reason why you need so many clutch changes on these cars....

[ossme]

V8Dom said:

hi
if you want to remove gear linkage and handbrake from the centre, can you not put a manual gear linkage and handbrake on the outside?? we run right hand gear changes on the right here no problems, not sure if its been done on left hookers but is it not a case of just fitting it on the otherside and redoing the linkage?? and then handbrake behind it, or even a merc foot mechanism for parking brake, offset under the dash...


IMO sounds too expensive and long winded just to move the gear/handbrake otherwise??

Dom

Edited by V8Dom on Wednesday 10th February 10:41

Hi V8Dom,

If I would go with CIMA it will be mainly because of the better gear ratio which is more suitable for road/highway driving. The pedals will cost 1k more so it doesn't add much to the original price and it will help in removing the shifter from the middle. It will also look cool and high tech which is a good thing.

I also thought about using a traditional manual and locate it on the left side. But I was under the assumption that this doesn't work with cable shifted transaxles?


Since I'm in the planning phase, I'm open for any kind of suggestions. I'm also looking for alternative gearbox options. So any suggestions would be appreciated.

These are the stuff I'm looking in a gearbox:
1- Easy to shift
2- Best gear ratio possible for road/highway use (100MPh = 2750~3000rpm)
3- Must be able handle power
4- Easy to install on an LS3/7 Ultima.
5- Reliable

[ossme]

spatz said:

ossme said:

Thank you for your replay guys,

The gearbox computer wont fully depress the clutch in slow speeds which helped in parking.

Probably the reason why you need so many clutch changes on these cars....

Well, I'm not too technical so I cannot say for sure if this what it was doing. But generally speaking the clutch lived lower than average.

[LuckyP]

Number 2 will be your problem pal. Are you quite sure 100mph @ 2750-3000RPM.

(that's a ratio able to go 233mph (or more) @ 7000rpm!)

Edited by LuckyP on Wednesday 10th February 21:38

[spatz]

LuckyP said:

Number 2 will be your problem pal. Are you quite sure 100mph @ 2750-3000RPM.

(that's a ratio able to go 233mph (or more) @ 7000rpm!)

Edited by LuckyP on Wednesday 10th February 21:38

yes the only problem might be the engine he needs to achieve this, the air is like a wall at these speeds and the effect is not linear !

[V8Dom]

mind you the 720 record car is listed at 233mph and 'restricted by gearing'..

I know the wall appears at high speed but the Ultima isnt that un-aerodynamic and Lemans cars in the 70-80 were doing upto 250mph and their aero isnt that different.

Ive listed the new m600 Noble gearing / horsepower etc etc in the 200mph thred. and their gearbox looks interesting too.. light , compact and takes the HP.

Dom

[spatz]

ok !

with my gearing and rev limiter set at 6500 rpm I should be able to reach the 200mph, will know when the snow has gone and the car is on the road, I just have the right "Autobahn" with no limit in front of the house.

[andygtt]

LuckyP said:

Number 2 will be your problem pal. Are you quite sure 100mph @ 2750-3000RPM.

(that's a ratio able to go 233mph (or more) @ 7000rpm!)

Edited by LuckyP on Wednesday 10th February 21:38

dont see a problem... my gearbox is geared for 262mph @ 7000rpm lol

[GTRCLIVE]

My Corvette does 2350rpm at 100 mph..... so I don't see a Problem either....

[ossme]

LuckyP said:

Number 2 will be your problem pal. Are you quite sure 100mph @ 2750-3000RPM.

(that's a ratio able to go 233mph (or more) @ 7000rpm!)

Edited by LuckyP on Wednesday 10th February 21:38

Actually, with 6th gear set to .711 and final gear is set to 2.916 the Ultima will be able reach 256MPH!

[ossme]

andygtt said:

LuckyP said:

Number 2 will be your problem pal. Are you quite sure 100mph @ 2750-3000RPM.

(that's a ratio able to go 233mph (or more) @ 7000rpm!)

Edited by LuckyP on Wednesday 10th February 21:38

dont see a problem... my gearbox is geared for 262mph @ 7000rpm lol

Interesting, which gearbox are you using?

Edited by ossme on Saturday 13th February 07:02

[ossme]

spatz said:

ok !

with my gearing and rev limiter set at 6500 rpm I should be able to reach the 200mph, will know when the snow has gone and the car is on the road, I just have the right "Autobahn" with no limit in front of the house.

You are not using a G50 porsche gearbox, are you?

[spatz]

i am with longer 5th gear and lsd