Street/Strip 1977 Skyhawk 231 Turbo/E85 Blow thru Carb

[stage169]

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[70styleVega]

I love this project.... I think an H-body and a DIY carburated/turbocharged engine is a marriage made in heaven. I've read about a couple of very streetable pump gas turbo projects that ran 11s with relatively low boast (6-7 PSI) that didn't even require intercooling. I'll be watching
Tom

[spyder_xlch]

I don't mean to hi jack but what's the advanges/disadvantages of blow through and draw through? I'm not a turbo guy but am becoming very interested. I guess I should do some homework.

[stage169]

I hope its a marriage made in Heaven I have read of examples of blow and draw through that do well but the performance is more limited to the draw thru setup. I've read Maximum Boost (Corky Bell) and HP Books Turbochargers (Hugh MacInnes) and both say there are to many compromises with a draw thru system. On a cool damp day the draw thru carb can ice up because with the correct air/fuel ratio you'll get a 45deg temperature drop when the fuel vaporizes in the carb. You can add heat to stop it but that is moving backwards for performance. You just don't find performance intake manifolds for draw through carb systems either (at least I haven't). I wanted a single plane thinking that would be the best fuel/air distribution for all cylinders. The Max-Performance Buick Engine book (Jefferson Bryant) that just came out mentions the Edelbrock dual plane intake as a good option for a blow thru setup. I don't know which will be best but maybe with this intake the stock hood will fit. Although a blow thru E85 carb isn't cheap it beats the price of fuel injection.

ESP is a company that sells a dual turbo kit for the Buick GN. They say two turbos surpass the performance of a single turbo with less boost which sounds good to me. I do know I can use two smaller turbos with smaller down pipes the size of dual exhaust (2.5"). But then there is the cost of another turbo and related parts. I really like the idea of E85. The turbo car I've watched this summer at Indy has 9:1 compression and no intercooler and hasn't had that first hint of detonation. He does have room to lean it out some but its a good sign now. The V6 Buick turbo engines don't go over 8:1 compression.

I plan to spot weld some headers and then let a real welder finish them. I just need to commit to one or two turbos. Two sure look nice!

[spyderman1977]

Brian congrats on the 109 Block. That in itself is a fairly major accomplishment in itself. They are not THAT hard to find but its still not that easy either. I might have found a nice small stash of 109 blocks but I need to go check the casting numbers first.

As far as the turbo setup I do wonder if you are going for performance or conversation? Most of the info out on the Buick performance boards show that the best way to get any sizeable amount of performance is through the FI route of the later T-type/Grand National cars. I think Ken Belle made some noticable power from his carb setup in the early years. I THINK...that the Pace Car Century in 76, which was turbo equipped was fuel injected. I do know that Smokey did a ton of work for Buick doing those years and I think it was his work with Buick Engineers that got the Turbo v6 idea going in the first place.

Either way it will still be a Buick powered Skyhawk

Paul

[stage169]

As far as the turbo setup I do wonder if you are going for performance or conversation? Most of the info out on the Buick performance boards show that the best way to get any sizeable amount of performance is through the FI route of the later T-type/Grand National cars.
Either way it will still be a Buick powered Skyhawk
Paul

Conversation! Its going to be a lot of that until that first trip down the strip. Believe me those guys don't want to touch the subject of a blow thru carb turbo Buick V6! The blow thru carb has been on the rise for a long time now with great success. With the electronics the GN guys say its all in the tune and I believe it. But I'm only wanting mid to low 10's and even if I use stock FI parts the cost is going to be more. Plus the stock FI intake has distribution problems and any little Buick FI add on cost big bucks. With the carb I'll make sure the tune is correct (wide band O2 sensors) and have a fuel pressure regulator that increases fuel pressure referencing the boost and I'm good. There are some converts in the GN group though Brian

[shoebox1.1]

ive seen that blow through on www.theturboforums.com im always on that site and it is a mandatory hang out for the blow through carbs. i would do the B/T like me just for the simple sake that its perfected now. the quirks of pre/post compressor are slanted to pre compressor carbureation!

[spyderman1977]

Just goes to show that technology can catch up after a while. Looks like it might bring new life to the older turbo carb setups especially if people are starting to have success. I passed on a complete carb turbo setup a few years back simply because at the time the FI setup was the way to go. Now might be the time to start looking for another carb turbo setup for another car.

Paul

[spyder_xlch]

Brian, thanks for explaining that. Now, about the single or twin turbo. You said "ESP is a company that sells a dual turbo kit for the Buick GN. They say two turbos surpass the performance of a single turbo with less boost". More performance with less boost? I'd think more boost = more power. Is it more volume then? Will 2 smaller turbos spool up faster then one bigger turbo?

[stage169]

ive seen that blow through on http://www.theturboforums.com im always on that site and it is a mandatory hang out for the blow through carbs. i would do the B/T like me just for the simple sake that its perfected now. the quirks of pre/post compressor are slanted to pre compressor carbureation!

I can't wait to hear what yours sounds like! How did your 4" downpipe fit along the firewall did you have to cut some?

Matt, I think the performance increase ESP is claiming comes from the fact that the boost they make with two turbos is cooler than with one. I like the GM high tech articles. Brian http://www.espperformance.com/twins.html http://www.gmhightechperformance.com/te ... index.html

[spyder_xlch]

The Perri brothers say that the kit can surpass the performance of a single turbo setup with less boost, which ultimately results in lower cylinder temps, less detonation, and fewer blown head gaskets (as well as increased engine reliability and durability).

Now that I like. Thanks for the link.