I have read the MKIV faq regarding TTC as well as a bunch of other threads.

I am ditching all the extra stuff related to sequential that I possibly can, and I know that I can wire the EGCV and IACV open. I have done that and removed the EGCV and IACV actuators as well. I have removed the two VSVs up top, and the EGCV VSV also.

My first question is, do I need to supply vac/boost signal to the EBV actuator at all once the control valves are wired open and their respective VSVs are gone, or will it just stay shut, which sould be peachy fine? I suspect it will just stay shut since the actuator should hold it shut unless it sees boost, right?

My next question is, can I also remove the wastegate VSV? I am a bit confused why the wastegate even has a VSV and how it operates. Does the VSV normally bleed boost pressure from the WG actuator in order to keep the WG closed longer and enable it to open faster once max boost is attained?

If I remove the WG VSV and plug the nipple on the WG that went to it, can I rely on the other pressure line coming off the compressor outlet to actuate the WG?

TIA.

 

No takers? I ask the tough questions I guess.

At any rate, I was looking some more at the vacuum diagrams, and it does look like the WG actuator bleeds off via the WG VSV until it is signaled to close, allowing the WG to see boost signal and open. I guess they do this so they can modulate the actuator quickly, and make it act more like an on off switch than a linear gate.

At least this is my educated guess. I think I will ditch the WG VSV and see how it behaves. With a boost controller, it looks like that VSV is bypassed anyways, so I don't think ditching it will hurt anything.

 

I would agree with your conclusions. The EBV will doesn't really need any effort by you once you go TTC. The boost controller will be doing the input on the wastegate (aka #1 Turbo actuator) anyway in the setup you mention. You mentioned the MKIV site. If you want to read till your blind on the twin mechanics also check out Stu Hagen's site 97supraturbo dot com. Unbelievable amount of info on the stock twins.

 

Thanks for the tips slappy As a matter of fact, I did read all of the info on Stu's site as well. You are right, there is a ton of good stuff on there.

 

Have you tried asking on supraforums? They know way more than CL

 

Nah it's all good man. I figured it out after staring at teh vacuum diagrams long enough lol.

 

LOl glad you did. Are you manual? Ive wanted to go ttc but im auto with a stock tc.

 

Yep, manual with 4.27 gears! Even before boost builds, this final drive ratio makes lag a non-issue. Currently W58, but once I get the R154 in, I will be VERY close to a stock 5-speed final drive.

 

Agree. I'm Auto with stock TC (TT Auto) currently in TTC and the 4.27 has gotten comments from other drivers about quickly it gets out of the hole. Waaay before boost even wakes up. Not much for getting to 180mph, but I think the 154 will be nice.