Lynn E. Hanover

[quote name='mike_rudy' date='Aug 4 2005, 09:20 PM']Lynn, would you happen to know how long your exhuast was before it was collect on your PP 12a?



Thanks, Mike


[/quote]





Mine were 22" inches. I use 24" now to get the bottom end a bit better. The driver tends to get below minimum RPMs too often. He says he dosn't but I film the gages in every session, and the film says he does.



Multipals of 10" to 12" work for just about anything. Then a 6" collector then a megaphone to a 4" diameter stainless muffler, then out the passenger door.



I saw a past National champion using 10" to a short collector then a tight turn and a long run clear out the back of the car.



For under 9,500 RPM, the long run to a collector at the rear bumper is good for low end power, and covers up mistuning better.



Lynn E. Hanover

heretic

Just judging by what I am told. Mr. Hanover claimed that his slick-shifted transmission shifts slower than his Saenz. I have no experience with the Saenz unit to make a judgement for myself.

mike_rudy

Hello, well still on the topic of transmissions, i am wondering if the gear ratio in the tranny is too wide for my peaky engine the gears are 3.35, 1.93, 1.29, 1.00, 0.675, i will ge able to shift basically clutchless but that is still fairly wide apart, as where if i go out and get an older T10 4 speed,



1st 2.56:1, 2nd 1.91:1, 3rd 1.48:1, 4th 1:1

1st 2.52:1, 2nd 1.88:1, 3rd 1.46:1, 4th 1:1

1st 2.20:1, 2nd 1.64:1, 3rd 1.28:1, 4th 1:1



That is much closer together, but now it doesn't have that initial deep dig 1st gear, so thats why i am wondering what to do lol



Thanks, Mike

Lynn E. Hanover

[quote name='heretic' date='Aug 6 2005, 11:39 AM']Just judging by what I am told. Mr. Hanover claimed that his slick-shifted transmission shifts slower than his Saenz. I have no experience with the Saenz unit to make a judgement for myself.


[/quote]





The point of the Saenz and other dog ring boxes, is that once the car is moving, the clutch pedal is no longer used.



The problem is that there is a procedure used in downshifting that must be learned, and followed lest the shock loads on the drive line fail a part.



We have broken trailing arms, and the front upper link mounting point, and of course the lugs on the dog rings.



It is counterintuitive to jam the accerlerator pedal down for each shift while you are attempting to brake at the maximum rate.



Also there needs to be a different shift lever speed employed during downshifts.



Upshifts are performed at nearly as fast as the lever can be moved. The throttle must be reduced slightly to unload the back cut on the dog faces, so the dog ring will disengage and move to the next higher gear.



So by the time the next gear is engaged the engine has slowed by some amount from lack of throttle setting and on engagement the aero load on the car has reduced the RPM difference between the next speed gear face (because ground speed is slowing) and the dogring.



So the RPM difference between the dog ring and the gear face is the rpm that will be lost on engagement and since that number will be far less than the calculated RPM drop for that gear change, there is less stress on up shifts than on down shifts.



The lower the rotating mass of the engine and transmission, the lower the stress on upshifts. This is obvious, because you need the engine to slow quickly, and the heavier the flywheel (for example) the more time it will take to loose any RPM.



On the very fast formula cars there is a switch that actually shuts off the engine during the upshift. The throttle is left open, and that slows the engine even faster. The shifts are so fast that you cannot hear that shutdown.



On downshifts, the throttle is depressed as the shift is made, so as the dog ring disconnects and passes through neutral the engine revs up and (since the clutch is engaged) it revs the whole transmission assembly with it. This brings the next lower gear face closer to the same speed as the dog ring about to engage it.



With practice, there will be no difference in RPM on engagement.



This is very important, because once you have started a max braking effort from top speed, you cannot afford any sudden decrease in rear wheel speed, caused by a clumsey shift. Lest you find yourself facing the wrong way around at high speed,

with a bunch of suprised looking drivers with their brakes locked looking at you.



I bought a set of gears from Allen Jones's formula one car at Watkins Glen. The gears were as new.

No wear marks at all. The FG400 formula one gears also fit my FT200 trans.



The giant over the road trucks, motorcycles and many riding mowers, have dog ring transmissions. It is not a new idea.



For shift speeds there is nothing close to a dog ring transmission. The smaller the peices (lower mass) the faster the shift speed. So any large trans converted to a form of dog shifting will be slower just from a mass standpoint.



My Richmond is shifting faster than stock, but still way slower than the Saenz.



I would like to get the Saenz rebuilt. The driver was getting much better just before it blew up the last time.



Lynn E. Hanover

13BTNOS

[quote name='mike_rudy' date='Aug 8 2005, 11:47 AM']Hello, well still on the topic of transmissions, i am wondering if the gear ratio in the tranny is too wide for my peaky engine the gears are 3.35, 1.93, 1.29, 1.00, 0.675, i will ge able to shift basically clutchless but that is still fairly wide apart, as where if i go out and get an older T10 4 speed,



1st 2.56:1, 2nd 1.91:1, 3rd 1.48:1, 4th 1:1

1st 2.52:1, 2nd 1.88:1, 3rd 1.46:1, 4th 1:1

1st 2.20:1, 2nd 1.64:1, 3rd 1.28:1, 4th 1:1



That is much closer together, but now it doesn't have that initial deep dig 1st gear, so thats why i am wondering what to do lol



Thanks, Mike


[/quote]



Since we are on the subject of transmissions and you are using a T5 have you looked at the Gforce T5 setup? http://www.g-forcetransmissions.com/tran_gt-5.asp The owner of Gforce has extensive experience with mazda rotarys and can figure out ratios you need for your setup. This is probably the transmission I will be using for my car total conversion is under $3000 and rating on this trans is 600 lb/ft in a 3000lbs car. Shouldn't be a problem for my 2000lbs Datsun 1200 with me in it. I was going to go with the GF5R but that was like over $6000 total.

mike_rudy

I am a 16 year old kid, $3000 is much to much for me to spend on a tranny, mabye down the line i will look at somthing like that, plus i will be making like a max 300 rwhp if i was super lucky, and the car will weight like yours 1900-2000 with me in it