Turbo formula tuning assistance (Page 2/2)
86dreamachine DEC 07, 12:08 AM
Thanks for the replies folks. I have considered water meth injection but I'm weary of unnecessary added complexity. Same reason I haven't ALREADY done a water to air conversion. As for e85 it's like foreign speak around here, i wouldn't even know where to get it lol and the added knock control could be gained with some octane booster in place of e85 if it's required. If I could make 16lb on 110octane without major mods past what I've already got in the works that'd be stellar. I don't know how realistic that is but I like to dream big when possible.

Should be noted that the previous owner told me at some point he had it up to 15lb boost but the car was "uncontrollable" at that level. Mind you he was mid 70s when I got it from him so idk how much I believe it point blank but it's something to keep in mind.
86dreamachine DEC 07, 01:31 AM
Forgot to mention the exhaust. The trunk has been cut and pieced back together to accommodate the entire exhaust in the engine compartment. I understand why I just think it's way too long considering it's a turbo car. If it was n/a I'd be okay with it for back pressure but for this I think it's unnecessary. Few 180° turns and at least 7ft of pipe post turbo to tips. Not to mention the heat output once the car is nice and warmed up. Currently has a spintech w/duals in this configuration... At some point (not soon) imma do something to shorten it or add the item in question below.

This is completely off topic from my original post but I'd still like to hear from you: I heard from a buddy about boost actuated exhaust cutouts (which I hadn't heard of up to then). Anyone have any experience with them and do they have a place in a turbo fiero application?
wftb DEC 07, 12:22 PM
My exhaust system goes like this: Turbo-downpipe-180 degree turn-catylytic converter-180 degree turn-straight pipe-90 degree turn-stub out under the bumper. Single outlet. All 2.5" pipe and mandrel bends in stainles steel. No muffler and it is only noisy when you really get in to it. Cruising along it is not loud at all.

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86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

[This message has been edited by wftb (edited 12-07-2019).]

pmbrunelle DEC 09, 12:17 AM

quote
Originally posted by 86dreamachine:
This is completely off topic from my original post but I'd still like to hear from you: I heard from a buddy about boost actuated exhaust cutouts (which I hadn't heard of up to then). Anyone have any experience with them and do they have a place in a turbo fiero application?



In some modified turbo cars, the wastegate flow does not merge back into the turbine discharge pipe.

Instead, a separate exhaust pipe is used for the wastegate flow... the wastegate pipe will only convey exhaust gas at maximum boost, uncorking the exhaust at that point.
Often, no muffler is used on the wastegate pipe, so it is called a "screamer pipe".
86dreamachine DEC 09, 05:57 AM
Pmbrunelle, i wasn't talking about an external wastegate (which is present on this build) I meant a dedicated straight pipe post hot side directly out the car (decklid in our case) so you'd maintain your full exhaust, wastegate, etc but when you reach your boost number you ditch all the excess back pressure and could in theory pull some extra horse on the top end. I've seen some folks pull a BUNCH of "free" horse on the Dyno with cutouts in boost. Mind you they are front engine and have more exhaust to bypass but even so the idea is valid in general was just curious if anyone here had heard of or seen them.
wftb DEC 09, 02:51 PM
Lots of new performance cars have electronically operated muffler cutouts from the factory. All they do is bypass the muffler when you have the car in track mode usually. New top of the line Camaros have them, 1ZLE? not sure of the model.

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86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms