80 Regal sport coupe blow though conversion

el vato

New Member
Hello everyone,
I'm new to the forum. I bought a 1980 Buick Regal Sport Coupe a few years back. engine runs good, lots of work done. 15 psi of boost on premium fuel. audible knock if I get past 15 psi. this draw-though system seems to be alright if you just want a fun car for the weekend. but I'm thinking I want to convert it to blow-through and see if i can get more out of the engine. I've seen some of you have done it before. so before i start collecting parts and ripping the top end apart and fabricating stuff. is there any hood clearance issues that i should be aware of? If you guy dont mind pointing me in the right directions or liking the threads I should be looking at, that would be highly appreciated.
I currently have a weiand smokey yunik intake. I read that this is one of the preferred intakes for this job. but dont have the plate adapter for the carb. have not looked at any carburetors or turbo assemblies yet.

thank you
 

WarWagon

Caustic Cacophony
First hand experience: This idea will cost you at minimum one engine rebuild during tuning/learning, Easy to build tough to stay together.
I'd suggest an throttle body EFI over the carb going into 2023 now, the price is good for the features. You can still do it with a carb and it will work however it is not forgiving.
Hood space isn't a problem especially with a turbo hood on.
I have a taller blow through setup and fits under a normal Regal hood.
Good call on the Weiand intake manifold, a KB #1 manifold is just as effective and 4bbl 4.1 v6 manifold is a good backup.
The exhaust will need stock '86-7 headers or aftermarket to get the turbo mounted on the header, turbo selection is better then.
The entire fuel system needs to be tip top either way "carbs or EFI" don't cheap out on any of that. E85? If you can do it.
Ignition and what will be controlling it must be addressed:
J&S safeguard alone or piggy backed with a CDI ignition box is good.
 

WE2Regal

Active Member
You didn't state what your goal for the car was, but it sounded like you wanted a fun street driver. Your doing pretty good if your getting 15 PSI from your carbed draw through turbo on pump gas. There are some things that can be done to get more from it but nothing near what a blow through setup can offer. There would be a big HP difference converting to blow through even at that same 15 PSI. For a street driver, a blow through designed Holley carb mounted on that Weiand intake, a small stock size 86-87 turbo, free flowing 86-87 headers and intercooler would probably get you the performance increase your looking for without breaking the bank. Add to that an ignition system to control timing and a fuel pump and regulator will be necessary to feed it. There will be several things to plan ahead for. You will need to plumb an oil feed line to the turbo and a drain back line. The up pipe from the turbo to the carb hat will have to be custom fabicated. It's much more involved switching to blow through than people think. I would start by modifying the fuel and ignition system first before converting while you collect the other parts necessary. That way the car stays in running condition and you can still enjoy it. Then when you have all the necessary blow through parts, you can begin the swap and the fuel and ignition are already done. I've seen too many try to take on too much at once and end up with a non running unfinished project.
 

WE2Regal

Active Member
The carb adapter for that intake is Weiand part #7471. If it is missing, that is a bit of a problem. Very rarely do they come up for sale separately from the Weiand 7541 intake. You could make one by using a Holley Dominator carb gasket as a template and adding the 4 additional mounting holes like on the Weiand intake. 4 holes on top of the intake mount the adapter plate to the intake and the other 4 are for mounting the carb to the top of the adapter plate. Those 4 adapter plate to intake mounting holes will have to be countersunk to allow for the socket head mounting screws that screw into the intake to tighten down below the surface of the adapter so the carb can sit down flat.
 

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WE2Regal

Active Member
Here's a top plate I had made to mount a draw through turbo on top of the Weiand 7541. It didn't need the countersunk holes since the turbo 3 bolt flange sat in the middle and I only needed 4 of the holes to mount it.
 

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el vato

New Member
I will take your advice on EFI. I've always been hesitant about going this direction because I personally have never used them. I installed a J&S box right away. the factory system didn't work. knock sensor was broken and nowhere to be found. I installed it with the factory distributor. I just cut the harness and connected the wires to give mag pickup input to the box and the trigger signal to the 5 pin module in the factory HEI distributor. I cannot do E85, only four stations in Canada and I'm on the other side of the country.

I did not state the goal but you got it. fun street car. fabricating wouldn't be a problem. oil feed lines and pipes I can make myself but it looks like I will have bring the template to the local machine shop to have the adapter plate made. but that's a bit down the road. I definetly dont expect this project to be done tomorrow. I can be patient.
 

el vato

New Member
I will try to upload some pictures and a video of the car running when I get a chance and there is light out
 

WE2Regal

Active Member
Making a plate like that is much simpler these days. The plate I had made was done entirely on a waterjet machine. You just have to know the hole size and precisely measure the center to center measurements between the holes. All the dimensions are programmed into a computer and the machine goes to work. The guy who made it for me charged me $25.00.
 
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b4black

Well-Known Member
I'm in the process of converting over to blow thru. It's basically a 86/87 exhaust, turbo, intercooler and fuel system set up with an HEI distributor and a holley carb. So far, I'm mocking everything up to see what fits where. I'm using a lot of 'spare' parts from other people's builds. The key to it has been a Champion AC delete bracket for an 86/87 engine. This moved the alternator to the other side and mounts the 86/87 power steering pump. The distributor, upper radiator hose, turbo inlet hose and carb hose all want to be in about the same spot on the front of the motor. Looks like it will all fit. I did have to remove the inner support of the hood to clear the carb bonnet. It fits nicely under the hood bump.
 

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el vato

New Member
I'm in the process of converting over to blow thru. It's basically a 86/87 exhaust, turbo, intercooler and fuel system set up with an HEI distributor and a holley carb. So far, I'm mocking everything up to see what fits where. I'm using a lot of 'spare' parts from other people's builds. The key to it has been a Champion AC delete bracket for an 86/87 engine. This moved the alternator to the other side and mounts the 86/87 power steering pump. The distributor, upper radiator hose, turbo inlet hose and carb hose all want to be in about the same spot on the front of the motor. Looks like it will all fit. I did have to remove the inner support of the hood to clear the carb bonnet. It fits nicely under the hood bump.
looks like I may have to upgrade my pulleys then. where do I find one of these brackets?
 

ShawnR

Fixer of crap..
Are you planning on keeping the distributor for ignition? It certainly complicates things "space wise".

I went with a cam sensor and LS coils. It is an adventure for sure, but you will learn a LOT.

IMG_20210912_150806552_HDR.jpg
 

ShawnR

Fixer of crap..
I'm in the process of converting over to blow thru. It's basically a 86/87 exhaust, turbo, intercooler and fuel system set up with an HEI distributor and a holley carb. So far, I'm mocking everything up to see what fits where. I'm using a lot of 'spare' parts from other people's builds. The key to it has been a Champion AC delete bracket for an 86/87 engine. This moved the alternator to the other side and mounts the 86/87 power steering pump. The distributor, upper radiator hose, turbo inlet hose and carb hose all want to be in about the same spot on the front of the motor. Looks like it will all fit. I did have to remove the inner support of the hood to clear the carb bonnet. It fits nicely under the hood bump.
Are you planning on running an intercooler eventually, or going E85? I only ask to see if you want my DYI carb hat that I used before the intercooler was installed. I couldn't figure out any way to get from the turbo to the throttle body that didn't have a bunch of extra plumbing.
IMG_20200929_185924768.jpg
IMG_20200927_133010933.jpg
 

b4black

Well-Known Member
looks like I may have to upgrade my pulleys then. where do I find one of these brackets?



I had to do a little tweaking to one of the mounting posts to get the HEI distributor to clear. This would not be an issue if you use a smaller non HEI distibutor.

If you plan on using the HEI, I can take some pictures to show you want I did. (Removing the vacuum advance was part of it.)
 

WE2Regal

Active Member
Are you planning on keeping the distributor for ignition? It certainly complicates things "space wise".

I went with a cam sensor and LS coils. It is an adventure for sure, but you will learn a LOT.
I noticed that you have another big advantage for plumbing a blow through system. That Weiand air gap with the small block Chevy style thermostat housing. With every other intake, you are limited with the water neck direction by a factory style thermostat housing that never seems to point in the direction you need. With that intake, you can get a water neck that swivels in any direction you want it to.
 
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ShawnR

Fixer of crap..
I noticed that you have another big advantage for plumbing a blow through system. That Weiand air gap with the small block Chevy style thermostat housing. With every other intake, you are limited with the water neck direction by a factory style thermostat housing that never seems to point in the direction you need. With that intake, you can get a water neck that swivels in any direction you want it to.
Kinda sorta, I bought a bunch of different thermostat housings and couldn't get anything to look right. I had the option of having the heater hose go over top of the intake tube (to the turbo), but that just looked goofy. I ended up making my own contraption so the heater hose would go underneath the air inlet. I did add a air bleeder screw on top of it after this pic was taken.
 

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