Hello, I am seriously considering running a 700r4 in my 87 GN. It is around the 500 HP level and the 200 is burned out-(bought it this way). Anyway, Ive been running the 700 behind my 455 pontiac GTO for years and have made it live. Part wise it is abvious that the 700 is stronger as it is based on the 350. Where as the 200 is based on the 200 metric 3 speed. I am on the learning curve as far as turbo is concerned. My question, will the lower 1st gear in the 700 , and the larger gear split which causes a larger gear drop when going from 1st to 2nd result in a slower car?
Is it called turbo spike? This must be the case, because it seems like there would be more conversions if not. Also, when building the 200 for power, is a solid input shaft needed? I am aware of using the other hardened parts. Thanks very much
I think you may find the 700 is weaker than a properly built 200R4
From what I have heard you may have to change diff gears to higher ratio because of the 700's low first gear. The 3.42 seems to work the best. I tried a 3.73 and it was too low. By the way I have a new (in the box) GM 8.50/3.73 gear set just sitting in garage collecting dust.
Phil
There seems to be a mix of opinion on strength. As mentioned I've run a 700 in my GTO (565ft.lbs. ,460 cu.in) with 3;31 and a heavy 4000lbs. I went thru 3 TCI units and finally decided to learn the thing myself. When using the Transgo kits and extra clutches, etc., I found the friction to last wonderfully. What broke, you may ask? An OUTPUT shaft, and a band eyelit fractured. Also, many hard surfaces seemed to be "distressed" at 30,000 mile intervals. I seldomly ran slicks.
The 700 is supposed to be similiar to the 350 strength wise. Even this cannot be exact as a 350 has a solid input shaft (unless it's a 350C). In this same gto from 1971 to 1994 (about 300K miles) the 350 lived flawlessly until it broke an input shaft. (a hard barker). Anyway I know that there is a bigger input shaft on the 700vs the 200, and bigger planets. So if I almost never broke a 350 and then seemed to pound the 700 in the same car I am really scared of a transmission with smaller parts than either.
Gear ratios may supercede strength issues. Phil, your info using 3:73's is a near perfect comparison for my comparison. After doing the math here is what I've found. If using the 700 with it's deep 1st, it would be like using the existing 200 AND a 3:82 rear ratio! So clearly if your 3:73 is too much then so is th 700's internal 3:06 1st. The deep gear spread may be even worse for a turbo. Does anyone know? Is anyone aware of a 700'd GN? Guess I'll be requisitioning some hardened 200 parts.
Thanks, Rick
I've known of at least one person who tried a TH700-R4 in a TR and they weren't happy. The ratios just didn't suit things well, and connecting everything up was a pain due to different case length, etc.
Rick, et al:
There is a well-known performance transmission builder here on Long Island that custom builds and services many overdrive transmission setups, including the 700R4, 2004R, and even has an overdrive tranny based on the Ford AOD, known as the 4STB, which can handle well over 800 horsepower with no problem when used as a manual shift/transbraked unit. The 4STB is available to bolt up to any GM, Ford, or Mopar engine, through custom bellhousings.
The builder is Freddie Brown Performance (www.fbperformance.com), located in Brentwood, NY, and has developed an excellent reputation for custom building many "bulletproof" overdrive trannies for quite some time.
Visit the website and you will see that he can build a 700R4 to handle 475hp, or even a 2004R to handle about 500hp. Keep in mind that all of the custom-built trannies that FB builds are custom-suited to vehicle weight, camshaft, power-adder (ie. TURBO!), rearend gear ratio, etc., etc. (check out the "Converter Application Form", and you will see how detailed the build-up is, and what it is based on).
Now, you may be thinking that I work for FB or something, but as a matter of fact, my only direct association with the company has been through my friends and their purchases of custom trannies from FB. For example, a friend of mine has a DFI-equipped twin-turbo 302 '86 Mustang that includes a 4STB FB Performance tranny that was built keeping in mind of the twin turbos, weight of the car, etc. This setup was purchased for $3200 (including case core charge), including torque converter.
Another example is a different friend of mine purchased a 4STB tranny for his '69 Pro-Street Chevelle, that is powered by a Merlin 509/540 hp BBC. Again, the tranny was suited for the Merlin BBC, its cam, vehicle weight, gearing, etc. Again, this setup ran about $3000 (including case core charge) including TC.
As this has been ONLY my opinion of FB Performance through experiences that I have witnessed, and the reputation that FB has developed, keep in mind that these are merely suggestions, not guarantees. I hope this can shed some light on different possible trans setups for the TR.
By the way, FB sells 500 hp-capable 2004Rs for about $1500, including TC, and will ship anywhere within the U.S.
Check out "New Items" to see a pic of the 4STB.
Good luck on your search, Lou
well guys, i need some hardcore convincing to switch me from a 700r4. I'm gonna be dropping a TTA motor in my GTA this March. I have a nicely built 700r4 lined up for $400. Now people are telling me to go 2004r but i see people selling ones that need rebuild for $400 alone, not to mention having the DS cut, new x-member and a new torque arm. Thats around 700-800 bucks BEFORE the tranny even gets rebuilt....is that 700r4 THAT bad for a turbo 3.8?
Louis, Thanx for the Floyd Brown info. I have researched this trans before for my GTO and was a little dissappointed that it was AOD based. The other hang up? It has to be manually shifted. I am absolutely sure a well built 700 can take the TR, its worst time would be at the tracks with traction obviously. But it did take my tork monster GTO with a 12 inch convertor. This makes two things occur, immediate big block tork is more shocking to hard parts and a big convertor holds more kinetic (spline stripping) power. This , cranking into a slightly less easy to turn 3;31 rear in a heavier car. In the GN, a smaller converter, 3:42 rear, lighter car, and tork which has to build (barring foot brake action) I can the 700 lasting for a long time.
But alas, I just am scared of slowing the GN down. Doing some math on the 400, 200r, 700r gives some interesting results as far as 1st 2nd gear drop go. With good ol 400 its 1.0, 200R=1.17 and 700=1.44. I am thinking the gear drop is the worst thing. And Phil didnt like the low gear of a 3:73 which is what a 700 would mimic in 1st. Does anyone know from a turbo standpoint why and how much a 700 would hurt the GN? Thanks, Rick