Th400/th350 Question

[turbotwister]

hi,
is there a way to get a th400/350 to work properly on a turbo car for normal drivability?it seems that if the car goes into boost the modulator will think the car is at full throttle causing it to shift very late even if you just dip into the boost.i dont have one in my car,but have been thinking about it and dont know how this can be made to work properly.fill me in.

thanks,nick

 

[azgn]

manual valve body........you shift it

 

[chris718]

a mechanical modulator will do the job .it has a cable instead of a vaccuum supply to move the modulator in and out .we use them here on many turbo and supercharged motors with fantastic results.when you open the throttle it pulls cable to raise line pressure regardless of induction systems.www.ckperformance.com

 

[turbotwister]

thanks chris for the info.i dont see it on your website.email me the details(price etc.) turbotwister@comcast.net


anybody know any pro's or con's to switching to a th350/th400?

let me know your opinions.


thanks,nick

 

[mlabrecque]

I have just dropped an 87 GN engine into a 1981 Turbo Trans Am with a TH350 tranny. Should have it going in the next few days - I can let you know how things work out with it... I'm not expecting any probelms as the 4.9L that was in the car before was turbocharged and the tranny always shifted fine...

Maybe there is something different about the 81 TTA tranny? (or maybe I'm in for a surprise and this won't work properly).

Anyway, I'll post something here about this in the next few days once I take the car for a tear.

 

[turbotwister]

actually marc i do believe it is different.thecarburetor on an 81 turbo trans am is before the turbo so the vacuum port never see's boost.the fact that the throttle body and intake on a turbo buick motor are after the turbo means that as soon as the turbo creates boost there is no vacuum causes the problem.so you may experience the same problem.as soon as the turbo creates even the slightest boost at part throttle the modulator will see no vacuum causing the tranny to shift at a very high rpm or act in an irregular manor.try it out and see what happens and let us know.

thanks,nick

 

[mlabrecque]

Hi Nick,

Just an FYI - I did wind up getting a mechanical modulator to resolve this problem.

 

[turbotwister]

good to hear that it worked.i was wondering if one of those would work well.does the cable hook up in the same location as the 200r4?tell me how well it worked.

nick,