banzaitoyota

Come to the SCRX7 Club meeting Saturday and I will tel you about it.

slinges

My car is in VA or else I would. Can you PM me?

Jimmy325i

Miata gears will swap directly into the rx-7 cases... nothing new there.

Childish acts? If you say so. look at what he said to start it.

jacobcartmill

iTrader: (6)

lets hear more about this 6 speed miata engine bolting onto the FC... what all do you have to do?

Liquid Anarchy

iTrader: (2)

After researching the Miata 6-speed, there are only 2 things you need to do...

cryo-treat engine internals, and make a custom bell-housing

scathcart

HA HA HA HA.

Got any proof to back this up? Or is this more hollow, unfounded Bullshit?

Compared to a regular NA, the GTU's has a 0.743:1(calculated from total gear ratio) as opposed to the stock OD's of 0.711:1 (S4) or 0.697:1 (S5) of other NA's.

The stock NA's run 134 mph top speed. The GTU's run 135 mph.

A TII, with 40 more hp, and a 0.762:1 OD runs 146 mph as a top speed.

Hell, even the FD with 255 hp and better aerodynamics doesn't even hit 160 mph.

No way a 0.85:1 ratio is going to create a top speed of 160 mph in an NA. Try 140-142 mph.

Keep dreaming, buddy. It's not the gears you run out of... its HP.

scathcart

I agree.

Look at what you are saying:
"Well, he started it!" God, its like something you'd hear at a playground.

Jimmy325i

You also said stock.....

Sean, Do you know what mechanical advantage means? Gearing will change the top speed potential. HP curves change the top speed potential. 10K rpm engines change the top speed potential. @ 9600rpm in 4th I should be approaching 160mph. (been a while since doing the math, but liquid and I crunched #'s on night and its pretty cool the potential)

And yes I'm fully aware of the increased drag the car has at that speed. I seriously doubt terminal velocity is 142mph. If the roads clear off I'll do a GPS top speed run this weekend and see what she'll do with stock gearing.


Something to be aware of about the previous comment which was brought back from the grave. At the time there was not a single post I could make which would not be disputed even if I said my car was grey. Someone would argue that to the core. I probably could've used better tact but didn't. So sue me....

Makenzie71

so when will this thread get back to finding me a six seed?

scathcart

Well, by your comment, we can only assume it would be stock, since you didn;t mention horsepower. If you had said a 300 hp BP NA, then yes, I would agree. Am I to guess? When you just state NA, it places the assumption of stock.

Sean, Do you know what mechanical advantage means?
Ha ha ha ha.
Eng. phys student.
Are you aware of what reality means? Still waiting on that timeslip or dyno, cowboy.
Ha ha ha ha ha. Jesus Christ, Jimmy.
I think it might be entertaining to hear your explanation of mechanical advantage, though...


Gearing will change the top speed potential. HP curves change the top speed potential. 10K rpm engines change the top speed potential. @ 9600rpm in 4th I should be approaching 160mph. (been a while since doing the math, but liquid and I crunched #'s on night and its pretty cool the potential)
This the same math that calculated 160 mph? God, I hope not. Assuming you used the stock circumference tire numbers in your calculations, a direct-drive 4th gear, and stock 4.10:1 rear-end gears, you would be seeing 160 mph at 8932 rpm. Why not just rev your motor up that high then?

And yes I'm fully aware of the increased drag the car has at that speed.
Are you really? Can you provide the calculations to prove this for me? How about this one: assuming no other changes, what is the difference in hp required to go from 135 mph top speed to 160 mph?

I seriously doubt terminal velocity is 142mph. If the roads clear off I'll do a GPS top speed run this weekend and see what she'll do with stock gearing.
Should be around 150 mph assuming your mods.

Someone would argue that to the core. I probably could've used better tact but didn't. So sue me....
We argue b/c you make ridiculous claims and can't back them up.
Remember what happened to the French scientists who claimed to have perfected cold fusion, but could not reporduce the experiment?

scathcart

Now. You're on your own, pretty much.

Why do you want a sixth gear? I may be your best source on this subject...

Mr. Eccentric

Cost vs. benefit is a wee bit of a damper on this one.

Makenzie71

I've driven several 6spds and just prefer the extra gear. I'm not in for performance or that extra 1/100 of a second..I just like six gears.

Now what me and Jimmy325i were thinking is this...

I can get a toyota 6spd for next to nothing. The bell housing comes off I believe. I would have to find an RX3 nell housing...and for cheap...and then adapt the two. Then it would simply be bolting the flywheel on the seven...which MKIII fly fits so I imagine a MKIV would too...and then clutch and stuff. The only probe with doing this is the starter...but I'm working on it...

jacobcartmill

iTrader: (6)

damn, mk4 6 speed would be badass in an FC. those transmissions are beasts.

Makenzie71

I know...and imagine getting one including a new clutch for $500. He's got it sitting on shelf waiting for me to figure something out...of course I need a running car first...
He thinks I can't do it...it's kinna a bet...if I can I get it for $500. If not he gets his tranny back minus $250.

Bridgeported

There are companies that make adaptor kits to connect the rotary engine to the Toyota gearbox. The supra 5-spd is one of the most comman gearbox upgrades in New Zealand, Peurto Rico, Australia, and other places.
The 6-speed has been put in also, but not near as comman as those others since the gearbox alone would cost about 5-times as much.
I could care less about having 6 gears, but when I reserached transmission options for my planned 850-950 rwhp 20B RX-7, there are only 2 transmissions I narrowed it down to. Coincidently, they are 6speeds. The T56 unit found in newer style Trans Ams and Firebirds, and the V160 unit found in Twin Turbo Supras. Both gearboxs can handle the power I will make.

So you want a cheap 6-speed? Here are some stock 6speed transmissions which handle serious power (all them over 600 rwhp): 300zxTT, SupraTT, Firebird/TransAm, RB25DETT Skyline, others?
You may have to change to a different ratio rear end to get the proper gearing, depending on your engine setup.

Don't bother with the Miata gearbox if you plan on making serious power with your engine. It might have 6 gears but it's half as strong as the TII transmission.

Jimmy325i

Sean, Ever heard of undersized tires? Part of my mechanical advantage. Seeing as how my speedo is off 9mph at 70, it takes a few more revs to get me up to speed, but takes less time to wind her out there.

attomica

This place is in Australia. They make a dogmission that's apparently the best you can buy. It's a sequential six-speed. Very nice, but I think it's around $6000.

Guru Dogmission

Oops, sorry. It's a five-speed, but:
"Shift times are measured down to 35 milliseconds."

You don't have to use the clutch while in motion either, just to start. Then you rev-match to down shift or slap it into next gear to accelerate.

Damn, I'd love to have one of these!

jeremy1

A company named TFR makes 5- and 6-speed transmissions for both the FC (2nd) and FD (3rd). The FD 6-speed is about $8k.

scathcart

Maybe you should re-read my post. I stated assuming stock tires, since you didn't tell me what size you ran. Am I just to guess?

A stock NA will still not hit 160 mph with a 0.85:1 OD. You have yet to prove otherwise.

I think you are getting things confused with the way things work, Jimmy. You don't make a claim and have people prove you wrong, you make a claim and prove yourself RIGHT.
You NEVER do this.

Still waiting on your explanation of Mechanical Advantage, cowboy, not to mention the hp required to change a top speed from 135 to 160 without another factor change. C'mon, these are easy...

Jimmy325i

Sean, I had never said anything about being stock. Your assumption is what causes your issues with what I post.

I don't have a digital video camera. If I had 400 extra dollars to spend it wouldn't be to buy one so I can justify myself to you people.

I still havent received the new injectors and the roads are all nasty from recent snow so I didn't get to make a top end run this weekend.

4th gear is plenty tall enough to get you to the speeds I was mentioning. The fact that the OD in our transmissions is so friggin tall is what brought me into this thread to begin with. (I think I made this point on the first page)

I have far too much homework to do as it is to be playing math and physics games with you. Air density would dictate the cars drag at any speen making it possible to fudge the numbers in my favor anyways. Air density used for drag calculation being at denver and air density used in Gnome for HP would probably net an equation leading one to prove that the stock n/a in OD is capable of reaching 190 mph. I fudged my post in favor of the greater RPMs to err on the conservative side intentionally. Liquid and I had been playing mental gymnastics with a transmission gearing java calculator and both of us came up with similar findings. I do not log my tangents as when I am ready to act on some idea I very carefully calculate the solution at that time rather than just plugging numbers into a script and seeing what it spits out.

Based on the ease of accelleration up to my present top end of 135ish, it would be justified to assume a top speed of 160 would be attainable with more RPM in 4th gear. There's my hypothisis, and when I get the car runing to 10K I will test it and see what happens.

scathcart

No, my issues are with your BS statements. You didn't say MY N/A, you said an N/A. "An N/A" refers to any N/A, including stock.
Ever taken an english course, bucko?

I don't have a digital video camera. If I had 400 extra dollars to spend it wouldn't be to buy one so I can justify myself to you people.
Then don't make claims you can't back up. Keep the trash out of this place.

I still havent received the new injectors and the roads are all nasty from recent snow so I didn't get to make a top end run this weekend.
Convenient.

[b]4th gear is plenty tall enough to get you to the speeds I was mentioning. [/b[
Prove it, or shut up.

The fact that the OD in our transmissions is so friggin tall is what brought me into this thread to begin with. (I think I made this point on the first page)
Yes, and you complained how the transmission was poorly set-up. How do you come to this conclusion? The first four gears are set up for great acceleration, and fifth is set-up for lower RPM cruising. It works exactly as intended. Mind you, you were never much for Mazda high-dollar engineering, were you?

I have far too much homework to do as it is to be playing math and physics games with you.
Convenient. You have plenty of time to spoon feed bullshit onto this forum.

Air density would dictate the cars drag at any speen making it possible to fudge the numbers in my favor anyways.
No it woulldn't. I said assuming all factors the same exact horsepower. I stated this twice. Maybe your reading skills are at about the same level of your english skills.

Air density used for drag calculation being at denver and air density used in Gnome for HP would probably net an equation leading one to prove that the stock n/a in OD is capable of reaching 190 mph. I fudged my post in favor of the greater RPMs to err on the conservative side intentionally. Liquid and I had been playing mental gymnastics with a transmission gearing java calculator and both of us came up with similar findings. I do not log my tangents as when I am ready to act on some idea I very carefully calculate the solution at that time rather than just plugging numbers into a script and seeing what it spits out.
Great. So you do all this math, yet can't prove a single word of it. *cough*bullshit*cough*

Based on the ease of accelleration up to my present top end of 135ish, it would be justified to assume a top speed of 160 would be attainable with more RPM in 4th gear. There's my hypothisis, and when I get the car runing to 10K I will test it and see what happens.
Justified? Justification would be speed calculations based upon PROVEN horsepower (from that dyno we're still waiting for...) Yours isn't justified, it is a stab in the dark.
I'll wait for the test.

Lemme guess, no video for proof of this, either?
At least one of your friends must have a digitval video camera. Don't you have any friends?

Jimmy325i

Actually, I think its rather inconvienient.

I have a clutch job coming up this next week which will provide the money for my dyno tuning time. Then I will make you eat your words.

My issues with the mazda transmission are not that of how it was intended to be used. They have to do with my intended use.

You Sean, are a very negative person, I however am a very positive person. Who do you think has more friends? I find it humerous that your technical attack on my statements is so WEAK that you need to bring personal attacks into this debate. Thats a blatant sign of a very weak character.

Want to prove me wrong so badly, then come down to MN and do it in person.

NZConvertible

Based on the info you've provided so far, you'll need to rev to ~9,500rpm to reach 160mph. To go from 135mph to 160mph to need ~66% more power at 9,500rpm than you have now at whatever rpm you peak at. (If you're wondering, power required increses to the third power of speed, so (160/135)^3 = 1.66). Assuming (from your top speed) you're making ~165hp now, you're claiming you're going to build a street port engine that'll make 275hp @ 9,500rpm...

Jimmy325i

I don't run out of power though, I run out of revs. I can still pull in 5th from 140 but, I don't have the stability or the roads to keep going safely. Going back to a stock outer diameter tire will raise my now seen top speed by a large margin. Also my rpms climb at roughly the same rate through all gears, leading me to believe that wind resistance is yet to be a problem. The reduction of mechanical advantage from the larger than current tires may, in fact, change this. But I have yet to drive the car on stock rubber.