Looking for 9s all motor what auto trans?

1314 Views 34 Replies 17 Participants Last post by coupe1993, 2 mo ago

HIVOLTJ

Discussion Starter · 3 mo ago

Automotive parking light Car Wheel Land vehicle Tire

1991 GT AOD car I'm going to build a drag and drive unit out of. Looking for 9s all motor SBF bolt pattern auto trans.

Looking for something to hold up to 750hp or so reliably on a budget. I would like to do drag week, rocky mtn race week etc. Car we see minimal use outside of that but does need to be able to cruise 65-70 on the highway.

Car currently has 3.73 geared 8.8. Would be in "street car" classes requiring full interior etc. Some require 3200lb with driver.

Built AOD? Built C4? 4R70?

What would you run? Leaning towards a stout C4.

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21 - 35 of 35 Posts

azmack

· #21 · 3 mo ago

For your goal of running 9’s in the quarter, you car is no longer a street car, it’s a race car you can drive on the street, big difference. Unless you plan on driving a lot at highway speed then build for the track.

The TH400 has already been proven in a fox chassis with cars running faster than 9’s. Heck the TH400 has been run in a variety of chassis behind different engines making 1200+ hp. Lots of support for this trans, tons of aftermarket parts and it’s easy to freshen up when needed.
If you are happy running 9’s and don’t plan to go faster, then you should look at the 4R70W. Skip the AOD, even with 4R internals the pump still sucks plus you would have to run a manual valve body, even then you are at the mercy of the valve body short comings.
The 4R can easily be built to hold 800+hp, there’s a couple guys who can build to 1000hp but this requires welding planetary gears etc. And yes , you will need an aftermarket controller or go manual valve body. Don’t fear the electronics, they are robust for this application. Heck you can lock the converter is 2nd - OD , this allows for extra rpm at the top end. I run a 4:10 rear gear. I can run at 70mph in OD with the converter locked and keep rpm around 2500rpm, fine for highway.

For race, TH400 is the only way to go. For street, a well built 4R fits the bill. FYI a good triple clutch 4R converter ain’t cheap so factor that into you decision.

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KEVIN$

· #22 · 3 mo ago

I second the 4R and as far as electronics are concerned the Quick4 is great. I can store multiple tunes in the controller and pull them up while driving. I THINK there are some older 4R's that may not need a controller or you can just have it built with a MVB.

IMO, the electronics would be better that way you can have a high stall for racing but lock up the converter on the highway bringing the revs down not to mention it has OD and all this can easily be programmed.

Dan Gilsdorf (Silverfox) can build it in a multiple configurations just talk to him and see what he can do.

ks

Reactions: 1

Tony Corley

· #23 · 3 mo ago (Edited)

azmack said:
For your goal of running 9’s in the quarter, you car is no longer a street car, it’s a race car you can drive on the street, big difference. Unless you plan on driving a lot at highway speed then build for the track

Not so sure I agree with this statement. 9 second street cars out there riding around with full interiors, a/c, p/s,etc. It’s not 2000 anymore lol. With that being said, I don’t know where a 9 second N/A street car would be competitive. In Drag Week, the N/A small block cars are in the 8.50s. For a street /strip car up to 2000hp, I’d go 4L80e. Strength and gear ratios of a Turbo 400, but with overdrive and lockup. If you don’t want electronics, use a MVB with a brake. It’s stronger the 4R70w, more aftermarket support, and you don’t have to deal with those slow assed reacting R70W Trans Brakes

LilRed86

· #24 · 3 mo ago

azmack said:
For your goal of running 9’s in the quarter, you car is no longer a street car, it’s a race car you can drive on the street, big difference. Unless you plan on driving a lot at highway speed then build for the track.

The TH400 has already been proven in a fox chassis with cars running faster than 9’s. Heck the TH400 has been run in a variety of chassis behind different engines making 1200+ hp. Lots of support for this trans, tons of aftermarket parts and it’s easy to freshen up when needed.
If you are happy running 9’s and don’t plan to go faster, then you should look at the 4R70W. Skip the AOD, even with 4R internals the pump still sucks plus you would have to run a manual valve body, even then you are at the mercy of the valve body short comings.
The 4R can easily be built to hold 800+hp, there’s a couple guys who can build to 1000hp but this requires welding planetary gears etc. And yes , you will need an aftermarket controller or go manual valve body. Don’t fear the electronics, they are robust for this application. Heck you can lock the converter is 2nd - OD , this allows for extra rpm at the top end. I run a 4:10 rear gear. I can run at 70mph in OD with the converter locked and keep rpm around 2500rpm, fine for highway.

For race, TH400 is the only way to go. For street, a well built 4R fits the bill. FYI a good triple clutch 4R converter ain’t cheap so factor that into you decision.

Before you badmouth the AOD you should look at a Freddie Brown AOD, like I said earlier, it's taking 1200rwhp like a champ with no hard parts breakage going on 5yrs and one refresh. It's been stupid reliable.

Reactions: 2

CDW6212R

· #25 · 3 mo ago

LilRed86 said:
Before you badmouth the AOD you should look at a Freddie Brown AOD, like I said earlier, it's taking 1200rwhp like a champ with no hard parts breakage going on 5yrs and one refresh. It's been stupid reliable.

That's a huge accomplishment, and I'd love to see what internal parts were upgraded. A lot of the 4R70W and AODE parts swap into an AOD, but the AOD VB and OD are hard to upgrade much. I like that Sonnax is producing both a much stronger forward drum, and lastly their direct drum kit. Those are huge weak link upgrades, both for the 4R70W and AODE, plus the AOD if they do go into them also.

I think they do, I have the AODE direct drum kit to build a 4R for my 92 Lincoln. I want to do away with the AOD lock up and input qualities, plus the automatic varying shift rpm's. So a 4R70W or AODE should have more predictable shifting, and yes they take some electronics to do it.

They both use just two, simply two wires, for all shift commands. You literally could shift one yourself with a couple of toggle switches if you were crazy enough to do that. I wired in two relays and one switch into my 95 Crown Vic in about 2002, to disable 3rd and 4th gear when I wanted to just have two gears. They are simple electrically.

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azmack

· #26 · 3 mo ago

LilRed86 said:
Before you badmouth the AOD you should look at a Freddie Brown AOD, like I said earlier, it's taking 1200rwhp like a champ with no hard parts breakage going on 5yrs and one refresh. It's been stupid reliable.

I didn’t bad mouth the AOD, I simply pointed out its weak points which are the pump and valve body.
I’ve built AOD’s with 4R internals, they worked well with the exception of the OD ban which wear pretty quickly and having to mess with governor weights / springs to get your shift points where you want them. The manual VB helps.
AOD valve bodies are getting or are scarce as are cases. In the past you really didn’t have a choice on auto’s so AOD’s had their day in the sun. Still lots of 4R’s out there and the Sonnax stuff is really good. The biggest difference IMO between AOD and 4R is the converter. AOD locks via a small steel shaft verse’s actually having a clutch in the converter. High Hp AOD use a 1 piece input shaft so converter lockup doesn’t exist. You can get triple disk 4R converters that will hold big HP. There is really no reason to run an AOD over a 4R . A 4R with manual VB is about as simple as you can get .

Reactions: 3

96pushrod

· #27 · 3 mo ago

Most people are surprised to hear aod’s can hold 4 digit power, but nobody is surprised when they hear a power glide or th400 will.

I wonder why

HIVOLTJ

Discussion Starter · #28 · 3 mo ago

^^^ lol

Thanks guys maybe I should just call silverfox and see what he recommends. I'd be cool with him sending me all the parts and assemble myself too... makes good content for the youtube channel.

Reactions: 2

KEVIN$

· #29 · 3 mo ago

HIVOLTJ said:
Thanks guys maybe I should just call silverfox and see what he recommends. I'd be cool with him sending me all the parts and assemble myself too... makes good content for the youtube channel.

I was just talking with him today over a private little project for my car.. Tell him to get to work on Kevin Slabys project...=)! He's a great guy and fun to talk with and won't BS you!

ks

Tony Corley

· #30 · 3 mo ago (Edited)

Again, I don't understand why anyone would waste time building a Ford based transmission for drag racing, unless you are in a class that the rules require it. The GM transmissions are just better, with more aftermarket support. C4's are weak, 4r70w's transbrakes are slow as molasses to react, and C6's are heavy as hell. Powerglide, Turbo 400, 4L80e. Pick the one that fits your needs, buy a $500 bellhousing so that bolts up to the Ford,
and roll with it

CDW6212R

· #31 · 3 mo ago (Edited)

HIVOLTJ said:
^^^ lol

Thanks guys maybe I should just call silverfox and see what he recommends. I'd be cool with him sending me all the parts and assemble myself too... makes good content for the youtube channel.

I have a spare Sonnax direct drum kit if you go that route. It's the kit with the drum and intermediate shaft merged as the one special part, and the required sun gear that will go over that shaft, plus the new direct piston etc. It's a $650ish kit, I don't need this one since deciding to swap to the 6R.

transmissioncenter.net

76656-01K Smart-Tech Direct Clutch Drum and Shaft Kit 4R70E, 4R70W, 4R75E, 4R75W - PATC - TransmissionCenter.net

76656-01K Smart-Tech Direct Clutch Drum and Shaft Kit | 4R70E, 4R70W, 4R75E, 4R75W. The first upgrade to eliminate every critical weakness.

transmissioncenter.net

76656-01k

toddturbo

· #32 · 2 mo ago

A c6 will do it but you may find yourself putting more power to it, to make up for the parasitic losses. They are heavy and they eat a lot of power. That's been my biggest beef with em.

514 in a fox body ran 8.94/150 with a C4. Switched to a C6 and it went 9.22/144. 3 tenths loss. It lasted a long time. In 17 I built a glide for him, he put it in and it went 8.84/151. No changes to the engine at all. The engine has been a trooper! He sprays an unknown shot at it once in a while and it will go low .50's at 160+. Around here it's mostly 1/8 mile stuff but it made a bunch of passes at Memphis and Noble and MoKan as well. Drives it on the street, or used to. Last I heard he got tied up with meth and it's nearly killed him.

if I were doing it I'd go 4R70W, and change the rear gear. 4R70W has a somewhat deep low gear which can work fairly well (depending on the converter) with a 3.73-3.55 gear. AOD and it's higher first gear ratio seems to like 4.10-4.30 in similar setups.

Reactions: 1

CDW6212R

· #33 · 2 mo ago

Try this web page for combinations of trans and R&P gearing, tires, plus shift points/rpm. It's interesting and may help with choosing rear gears, or the transmission.

Gearing Calculator | RPM and Tire Diameter to km/h - mph with Shift Tracer

Enter Gear Ratios, Tire Diameter and Diff Ratio to Calculate km/h mph and Shift Points with Tracer. Large Animated Gauges

www.blocklayer.com

azmack

· #34 · 2 mo ago

toddturbo said:
A c6 will do it but you may find yourself putting more power to it, to make up for the parasitic losses. They are heavy and they eat a lot of power. That's been my biggest beef with em.

514 in a fox body ran 8.94/150 with a C4. Switched to a C6 and it went 9.22/144. 3 tenths loss. It lasted a long time. In 17 I built a glide for him, he put it in and it went 8.84/151. No changes to the engine at all. The engine has been a trooper! He sprays an unknown shot at it once in a while and it will go low .50's at 160+. Around here it's mostly 1/8 mile stuff but it made a bunch of passes at Memphis and Noble and MoKan as well. Drives it on the street, or used to. Last I heard he got tied ndup with meth and it's nearly killed him.

if I were doing it I'd go 4R70W, and change the rear gear. 4R70W has a somewhat deep low gear which can work fairly well (depending on the converter) with a 3.73-3.55 gear. AOD and it's higher first gear ratio seems to like 4.10-4.30 in similar setups.

Solid post. I run a 4.10 gear, 3200 rpm duel disk converter with a 4R on a 26” tire and I can’t get through a 1/4 without shifting into OD. But I didn’t build my car for 1/4 mile, it’s all street and suited for 1/8 mile aka light to light. This is where the 4R shines with a 1.55 second gear. I actually short shift from 1st into 2nd since 1st gear mph is hit so quickly And also helps with traction.
The Holley Terminator X Max controls the 4R shift points so I can just mat It and go. I only make just over 400rwhp (N/A) so it works for me. If I was running 500 or above, I’d definitely swap to a 3.73 gear for sure and 3.55 with a turbo with the 4R. Gotta factor in car weight as well.

coupe1993

· #35 · 2 mo ago (Edited)

Fred Brown AOD here. Wide gear ratio option, non lock-up, manual VB w/TB. NA street/strip driven combo. Bracket 10.0s car in 2500-4000 DA. Have around 100 runs or so going on 5 years now. Not street driven as often over the past two years due to relocating.

Went with a spool and more gear over the winter (4.10's now, formerly 3.55 and 3.73 for the past 2 seasons) more cam and intake porting to balance the runners while dropping 140lbs. Looking for 9's on a regular basis and plan on running this AOD until it doesn't. So far it's been great, but there's no denying a built TH400.

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