2004R to 'braked TH400: E.T. Pick Up?

[turbonatr]

This question is for the guys who have gone from a 2004R to a 'braked TH400. How much e.t. have you guys picked up with the swap? My GN is now trannyless and it's time to get nuts with it. A race TH400 is going in and I wanted to get an idea of what kind of e.t. improvement to expect, generally.

 

[turbonatr]

No input?

 

[G McCall]

I'm about to have the same swap completed.
My expectations (based from experience by others) is not so much an ET gain but a dependibility gain .
The TH400 takes more HP so theoretically you would loose ET considereing all else equal. However, the transbrake will help ET provided other components are working giving the traction you need. Also, the transbrake should help you spool so there is another plus.
It 's up to you utilize the components for an ET gain.

 

[2quiktocare]

Dependability is not a question if the 200 4R is built right. Even with high horsepower. The only drawback with a 200 4R with a brake is about twice the cost of a 400 with a brake. The biggest drawback on the 400 is that if you street your car, you will hate life without overdrive. Your main concerns will be outright cost(200 4R), or the cost of drivability and fuel economy(400). IMHO,,,,,Mark

 

[turbonatr]

The car will e.t. better because I will be leaving off a transbrake with a suspension set up for just that versus the 2004R leaving off the foot brake. A buddy of mine picked up 4 tenths from the foot braked 200 to the transbraked 400 leaving that the same boost pressure. Leaving with more boost on the 'brake, he picked up more. I just wanted more than one example to go by.

This is a track only car that will see action every weekend. IMHO, a TH400 is definately the way to go for a track only car.

 

[2quiktocare]

I agree, if you are only running track, go with the 400 and save the money for sure. A 200 4R with a brake will launch just as well, but you are talking twice the money again. Save your bucks and put them towards some more go parts. lol, Mark

 

[quickt]

Originally posted by turbonatr
The car will e.t. better because I will be leaving off a transbrake with a suspension set up for just that versus the 2004R leaving off the foot brake. A buddy of mine picked up 4 tenths from the foot braked 200 to the transbraked 400 leaving that the same boost pressure. Leaving with more boost on the 'brake, he picked up more. I just wanted more than one example to go by.

This is a track only car that will see action every weekend. IMHO, a TH400 is definately the way to go for a track only car.

Not fair to compare T-brake tranny to footbrake tranny. If both trannys have t-brake the 200 would be worth maybe a couple tenths if you can hook the additional torque multplication of the 200s first gear. If you cant hook it up they would be about the same. If you have the correct converter for your 200 I doubt you will pick up anything with the 400 other than some weight and additional money in your jeans. Most who swap to the 400 from 200 had cheep tranny and converter to begin with. In that case you should expect to pick your car up. I have been doing LS1 cars that have 400s and going to 200s and they go faster with the 200. I do agree a race only car should stick with a 400 as there is no need for additional dollars for the overdrive if you dont need it.

 

[2quiktocare]

Well said from a man that knows first hand. Thanks Lonnie,,,,, Mark

 

[chris718]

FROM OUR EXPERIENCE WE HAVE picked up 2 tenths to 7 tenths .this is only when the 2004 s 2.74 would overpower the tires and the 400 with its 2.48 or our 2.28 would stick the fu#$in tires to the ground and plant the car to the ground gaining added traction and leave like a bullet .also in wide power band turbo applications the car will be able to fall on the fat part of the torque curve on gear changes and pick up mph and et by using the flywheel horsepower more efficiently to accelerate the vehicle with a th 400 verses the 2004r.many of you dont agree with me here on this but if the perfect ratio all the time for every combo was 2.75 / 1.57 everyone would have that.this is simply not true.certain applications will benefit from a numerically lower first and second gear and certain ones will kick ass with a numerically higher first and second gear .careful analysis of camshaft information,vehicle weight ,boost and cylinder head design will show the optimum starting line ratio and shift recovery rpm for given vehicle combinations to yield the best results.with a transbrake (using our 2004r brake verses our 400 internal lo second valve body in the same car behind the same engine with our 2.75 gear set)the 400 leaves harder than the 2004r because of the inertia of the backwards helix of the 400 planetary gears and the added weight.if you cant afford a 2400 dollar 2004r than a th400 at around 899 plus with a brake will definately do the job and wont twist up the output shaft at even 1600 plus horsepower.

 

[turbonatr]

Actually, I NEED to compare a foot brake 200 to a t-brake 400 because that is what I am trying to see the difference in. This isn't a debate over which will e.t. better, a braked 200 or braked 400. It is a thread asking people who have swapped a 200 for a braked 400. My buddy picked up e.t. with the braked 400, there is no room for debate there. It happened.

 

[chris718]

i only have the info available in the above post.sorry if it dont help.

 

[2quiktocare]

I don't think it is a debate, but the fact we are trying to compare oranges to oranges rather than oranges to apples. Which ever way you go, I hope it works good for you. I was just trying to show what your advantages and disadvantages were with the two units on an equally equipped basis. If you are just a track person, and no street, the 400 will be a great asset for the buck. Mark

 

[turbonatr]

Chris, You info was very good. Thanks for the input!

2quik, The GN is a track car only. 400 are WAY cheaper to freshen and I don't have to search far and wide to find a guy who can build one right like we have to do with the 200. My T is a street car and will keep it's 200.

 

[G McCall]

All great information here to copy for my information book.

 

[2quiktocare]

Good deal Turbo, the 400 will work great for you then. Mark

 

[Spooled231]

I did the 200 to 400 swap last year and absolutely love it. I was running anywhere from 7.45 to 7.60 @ 95mph with 1.6 to 1.7 60ft. at 20lbs of boost and 10lb launches. The first pass with the 400 resulted in a 1.58 60ft same 10lb launch and 20lbs of boost, 6.97 @ 98mph. I backed it up with a 7.01 and 6.93 with 60fts in the mid 1.5's

Thanks
John Martin
1986 Buick T-type
10.91 @ 123.6
6.93 @ 100.1