Well I finally got to the dyno this afternoon to see how much parasitic loss a TH400 and ford 9" really have. The car is identical to in all aspects except for the drivetrain. I swapped from an M6 with a 10-bolt with 3.73's to a TH400 and a moser 9" with 4.11's. Mods to the car are whisper lid/maf ends, and an exhaust cutout. Here's the numbers. I'll post the graph later tonight after I get it scanned.

Before
317.3 HP and 330.9 TQ

After
286.6 HP <img src="gr_eek2.gif" border="0"> and 353.8 TQ

I knew that there would be a loss in HP but I really did not expect to see 30RWHP lost. Weather conditions were similar on both pulls. Now at the track I really dont see a lost 30RWHP. Before the conversion my best time was a 12.74 @ 110 with a 1.98 60' Now my best time so far is a 12.56 @ 108 with a 1.74 60' Granted the better 60' makes up for alot of the ET but the MPH is only down 2 MPH. I figured with -30HP i'd be down more than that on MPH. Well there you have it for everyone wanting to know just about how much loss there is going through a stout drivetrain.

L8r

 

Thanks for the great info will....I can't wait to see the graph... <img src="gr_stretch.gif" border="0">

I figure after I dyno WITH programming, I will be around 340rwhp and 400rwtq....I figure I will only lose about 25rwhp considering I have a 12-bolt and a 3.73, which takes up a little less power...hopefully... <img src="gr_stretch.gif" border="0">

Well I can see that the conversion will be worth it figuring that you repeated the same time after...and thats on nittos... <img src="gr_stretch.gif" border="0">

 

Here's the graph.

 

What did you rev the motor to and what are the spaces at the end?

 

Sounds like a pretty expensive way to pick up
less than 2 tenths. <img src="gr_images/icons/wink.gif" border="0">

 

I'm sure it will pay off in the end for him...... <img src="gr_grin.gif" border="0">

 

[quote]Originally posted by 01-Z:
<strong>Sounds like a pretty expensive way to pick up
less than 2 tenths. <img src="gr_images/icons/wink.gif" border="0"> </strong><hr></blockquote>

Well I'd be more than glad to pay that AND not have to worry about breaking at the track. These 10 bolts scare the hell out of me

LAter <img src="gr_grin.gif" border="0">

P.S. What kind of converter you got in there?

[ February 12, 2002: Message edited by: Bob2of3 ]</p>

 

I am going to have the same setup.....

he and I both have the JW "J" stator 4500 converter...

I'm hoping for 11.8's with stock suspension

 

[quote]Originally posted by 01-Z:
<strong>Sounds like a pretty expensive way to pick up
less than 2 tenths. <img src="gr_images/icons/wink.gif" border="0"> </strong><hr></blockquote>

I did the drivetrain first because I'm planning on building a stroker motor and running a direct port kit on top of it <img src="gr_grin.gif" border="0">

The motor was at a stock rev limit and the spaces I think are just mess ups with the printer....car sounded fine all the way up to redline.

It's a JW 10" 4500 stall converter

L8r

 

Well at least you don't have to worry about breaking stuff now! <img src="gr_stretch.gif" border="0">

I wonder how many of the lost horses (if any) a Yank 4500 converter would get back.

 

why would it give back more....non-locking... <img src="gr_sad.gif" border="0">

 

A Yank would probably be near the same. I really like this JW converter and I'm very happy with it. It's nearly half the price of a yank and they are only about 45 minutes away from me if I need anything. I've driven a friends car with the same drivetrain I have but with a yank 4500 converter and it felt the same to me. Only way I could see picking up some power is with a lockup kit like yank makes for their TH400's now. Of course the stroker motor I'm building is a good way of gaining power too <img src="gr_grin.gif" border="0">

L8r

 

I think a good part of the MPH loss is the converter (yes, I truly believe a Yank would pick you up a MPH.) And some of it is just the fact that it's not an M6. What 1st gear ratio do you have anyway?

 

Hes got the 2.75 <img src="gr_stretch.gif" border="0">

[ February 12, 2002: Message edited by: BIGBOS ]</p>

 

the reason the TH400 dyno looks like it revs higher is because of the non-locking converter. The spaces are either an extreme case of that or the printer screwing up.

Ryan

 

I see...I will make sure to take pics of the graphs when I dyno to compare.. <img src="gr_stretch.gif" border="0"> I will post them sometime in march

 

This is some good info., great topic.

 

Precision Industries also makes a lock-up converter fot the TH400.
What is the benifit of a non-lock-up vs, a lock-up at the drag strip?Sorry I am a T56 guy,but might be making the switch also.
http://www.converter.com/95gmtorque.htm

see ya
John

 

When you lock it up it gives you a lot of the HP back at the middle to the end of the track there fore giving you more MPH....

Someone can explain in more detail..... <img src="gr_stretch.gif" border="0">