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View Full Version : B18c Gbox Ratios for track



ozswitch
17-11-2013, 07:43 PM
So I have purchased a JDM DC2R and was wondering what close ratio sets people use for track work? Car currently has a 4.4 FD but will switch that out to a 4.7 or even 4.9. Any of you guys have experience with close ratio sets and a 4.7 or 4.9 fd?

Extremer!
17-11-2013, 08:55 PM
Depends on what track you are looking to drive the car on. Wakefield , Eastern Creek etc. . I have installed 4.928 in customers car , and they are very satisfied with the results . 4.7 is a nice FD as it can be used fro both track and everyday , while with the 4.928 your going to more track (still can be used on street) .

Just to ask you what year is your Type R as the 98 and on has 4.7 ?! Still keep in mind if you have the 95-97 model and you have the 4.4 FD and you decide to go with the 4.7 you will need also to change 1st hear with the needle bearings . I can supply to you both either 4.928 or a 4.7 (complete) . We can also do the installation if you are in Sydney as well as install Carbon Synchros and many more stuff , just suggesting since you are looking in to opening the gearbox and changing your FD .

ozswitch
17-11-2013, 09:34 PM
Thanks for the help. Car is an IPRA car so no street driving just track. It is a 97 type r. I think the 4.928 would be a better choice but I will have to check my calcs to work out revs vs speed for somewhere like EC.

Extremer!
17-11-2013, 09:47 PM
What other mods are you having done to the car ?

Also as suggetsed above , since the car is IPRA better to install a set of Carbon Synchros , will improve a lot your shifting even at up to 11.000 RPM's .

ozswitch
17-11-2013, 09:53 PM
Just picked up the car today. Its fairly basic, has a kaz 1.5 lsd, and the usual other stuff like suspension and the like. Engine is relatively basic with just really an intake and exhaust. Need to learn how to drive the thing first as I am coming from an Evo. Just the one thing that jumped out at me was the gearing. I think there is room for improvement there and it can help hide some of the cars lack of power if I can sort it out.

Extremer!
17-11-2013, 10:04 PM
So I assume that first that you will want to see how it reacts and feels etc. . So what I recommend is the 4.928 FD , with a set of Carbon Synchros and a Flywheel with a good clutch kit on . Your clutch kit will be loosing a lot of power as the friction matterial won't last to the abuse of the track and you will be loosing power ones it worms up . (This depending on the brand .) Also 3rd gear usually starts crunching and 4th starts getting a little tight , that is why I suggets also the Carbon Synchros , the brass material from the factory ones , will simply not do for the job .

With those 3 stuff the car will be completly different .

chez00
18-11-2013, 06:53 AM
As far as final drives go, get the shortest gearing you can where you won't run out of speed at the end of the longest straight you run at. Should be a reasonably easy calculation to do. I'd be surprised if you ran out of wind with the 4.9 although I'm not familiar with the tracks you run at - probably Philip Island would be the only one where you'd get close that I know of.

You also asked about close ratio sets. the '97 box has the "closest" ratios of all the hydraulic gearboxes most notably 4th and 5th (1,2,3 are the same as the 98+). Closer sets can be had but I'd recommend just swapping out the final drive for now and then working out any places on the track where you could drop gear changes by moving to a closer ratio set. The final drive swap would be the most noticeable change.

Depending on how old the Kaaz is, it may pay to have it checked while your box is apart to make sure you've still got plenty of breakaway torque as the clutches wear out eventually.

cbauto
19-11-2013, 09:57 PM
Chez00 & Extremer!

Can you supply oem type r LSD, 4.7 FD, 1st gear etc....?.?.?

If so, please pm me price and further details.

Extremer!
20-11-2013, 09:13 AM
Pm Sent