TRD Cross-Mission gearsets.... Lil help please.

[Touge Boy]

Hey all,

Not sure if this should be in here or one of the racing sections, but im after a little help from the guys a bit more experienced with setting up/racing track cars and a good understanding of gear ratios. My question is not whether or not I should buy it, because that's not what Im asking. Simply which one would suit my car better.

Im looking at a TRD Cross mission Gearset for my 86, and Im having a little trouble working out which one would be better for me. The car will always be NA, Im building a fairly aggro smallport or 20V in the next 6-12 months, And Im just trying to get the most out of it. When i purchase the gearset, the gearbox will also be rebuilt with all new bearings etc.

They come in 2 types, Type A and B. Type A Has even closer ratios, but Im not sure which one would suit my car better. (Hopefully the Type B as It's about $1K cheaper haha) The Type B gearset is around $1600 delivered as I type this with current exchange rate.

It's currently 4AGE Bigport hopefully making around 100kw's when tuned and about 130-odd with nitrous, using a TRD 3.9kg flywheel, Will shortly have TRD 4.56 gearset in T-Series rear end, and using 15 inch wheels with either 205/50 or 195/50 rubber.

Car is Used mainly for drifting. Basically trying to keep her right up in the powerband as much as I can. The CW+P will be going in first, plus the car will be tuned properly, with some more track time. Then the new gearset will follow.

Ive never been any good with gearbox ratios etc, and Im wondering which one would suit my car the best with the CW+P, tyre size, intended use etc. (You'd figure after years of playing Gran Turismo Id know exactly what im doing haha)

Stock Ratios -

1st 3.584:1

2nd 2.022:1

3rd 1.384:1

5th 0.861:1


TRD Type A Ratios -

1st Gear - 2.341

2nd Gear - 1.607

3rd Gear - 1.195

5th Gear - 0.886


TRD Type B Ratios -

1st Gear - 2.630

2nd Gear - 1.891

3rd Gear - 1.384

5th Gear - 0.861


Obviously, the type B is close ratio, and the Type A is even closer, but would it be too close with the 4.56 gears? As in 2nd gear would border on useless hard smashing the limiter? The Newara Imports 86 uses the type B set with a 4.56 CW+P, but also has a 200hp built 20V in it. Would driving style play a part as well? As in speed/line/aggressiveness?

And, Is it any stronger than a stock gearset? The OS Giken 1st to 3rd gearset was also stronger, but has now been discontinued.

And light that can be shed on this would be most helpful


Ben

[Celica RA45]

ok ben type a is for a rally car with say a 4.8 ratio .but what you can do is get the dearer 1 and ask for the 2.6 1st gear ratio
on the type A ratios it is dearer but you get all of the gears changed except
4th which you would need from your box any way
with the taller 5th it wont drop as much and the car will still accelerate

[Touge Boy]

Awesome. That actually really helped.

Although for the cars intended use, 5th gear is really neither here nor there, same as first gear. it's really 2nd and 3rd which will be used most of the time.

And actually, ive just noticed that 3rd is the same ratio stock and the Type B Gearset. So Realistically Im paying $1600 for a shorter 2nd gear. Fuck that. I might do what you suggested Celica RA45 and see if I can get the Type B 1st gear put into the set and run the type A set instead.

Would the Type A set be difficult to use, seeing as you said it was for a rally car with a 4.8CW+P? Maybe I should just change to something like a 4.77 CW+P and leave the stock ratio's on the box? seeing as then the Type A gearset uses a 1.195 3rd gear as opposed to the stock 1.384:1 Im wondering if it's actually worth the coin now.

Any ideas on it's strength too?

Ive also noticed the Albans gearset... anyone have any ideas on pricing and strength? I know there's a couple of people using them, namely the clubman guys too.

[jay70]

what do you actually want to gain from this?

[Celica RA45]

my mate has the rally gear set in his corolla with a 4.6 diff ratio and when he had the 4.3 at sandown he use to go back to 1st gear .he has the 4.6 now but with 2.3 it is a bit easier to get off the mark .with the 2.6 it would make it faster off the line ,but he only does super sprints so it not a problem /also he uses 5th at philip island down the long straight and also at calder and at winton uses every gear bar 5th
car ke25 corolla with black top 20 v in it

[Touge Boy]

Being used for the above and also for some more strength and peace of mind. I wont change to another gearbox because of the weight and simplicity.

Again more food for thought. Many thanks. The main track here is Malalla, but am intending on getting to some other tracks some time this year.

Just weighing up cost VS outcome ATM... I think Ill have to look into tyre sizing and a few other things before I get to this. Ill get it tuned and the 4.56 gearset in there, and then Ill have a better idea of what ratios I should have.

[Frak]

Ben, in N2 racing it was common to use gear set A or what is known as TRD5 with a 5.375 diff ratio, with set A, there is actually a bit of a gap from 2-3 which is noticeable due to the closeness of 3-4-5.

Keiichi use to run a TRD5 with a 5.375CWP in his 'road' car, later he changed to the TRD3(gear set B) gearset and a 4.778CWP.

The problem with running a close ratio gearset is that 1st gear is taller than normal, meaning that if you were to keep the 4.3CWP take off would be shocking, lots of clutch slip, changing to a shorter(numerically lower) CWP does make this better.

Many years ago I had a close set of gears in my RX3, 1 2.33, 2 1.77, 3 1.26, 4th 1.00 and ran a 4.88CWP, I use to run the engine to 10,300rpm which gave me close on 100km/h in first, a little clutch slip was needed but once on the go, the upshifts were very nice, once you have driven a car with a very close set of gears you will always want.

With my 86, years ago I thought about a close set of gears BUT didn't want to have to put up with a crap 1st gear(take off etc) so I adapted an MX5 6 speed in, 1 3.760, 2 2.269, 3 1.645, 4 1.257, 5 1.00, 6 0.843. So I have a 'normal' 1st gear, then if you look at 2-6, a nice set of close gears. I can have my cake and eat it too I am running this with a 4.778CWP

I'd recommend to you the TRD3(set B) with a CWP change, I think you will find they will be nice for drifting and spirited driving.

[Touge Boy]

Thats awesome frak... exactly what i needed to know. Many Thanks to you and Celica RA45. Appreciate it.

I was pretty sure on the Type B set with a 4.56 CW+P, but wanted some advice and experiences before I did anything. I also currently have 4.11, not 4.3, so it would be even worse haha.

As I said though, the tune, CW+P and N20 will come first, along with a change to a 195/50 rear tyre, and then the Type B set and probably a TRD short shifter to go with it.


Any Idea on it's strength? ive tried searching but Im must be failing at the internet. ive found plenty of info about the gearset itself, but not much about people actually using it and what sort of abuse it can take.

[Frak]

If you do decide on a gearset and get the box rebuilt, either by yourself or by someone, if you decide to use a short shifter REPLACE the synchro's.

The reason is this, the short shift changes the position of the pivot point and speeds up gear selection BELOW the pivot point, so if your synchro's are already a little scratchy with a standard shifter, they will definately crunch after.

[Frak]

Ben, these gearboxes seem very popular over the years in JDM racing, the weak point would be the synchro's.

Quaife do a dog box, I priced one years ago before deciding on the mx5 box, the quaife set were about 10K, hence the cheaper mx5 box option!

When deciding on a close ratio gearbox, determine how much 'daily' driving you will do, let me assure you, if you DO NOT go short(numerically lower) with the CWP you will get pissed off in stop/start traffic as you slowly start smelling you clutch disappear