Blowthrough build repeat.

[WarWagon]

Made the switch to 8AN feed fuel line from the pump to the rail. Now the rail is no longer deadheaded and the regulator is the last stop before fuel return.

https://photos.app.goo.gl/nyXMoWkkvPiKAAE99

I drove the car and it seems alright but I definitely could have hurt it some already but I need to look over a few things. It is very rich on fuel now something happend to the fuel table or somewhere I'll reload the tune on the EFI. I think I may plumb in a PCV I,have never ran one while this engine has been turbocharged.

 

[WarWagon]

Looked over the engine this morning, I only seen the dip stick had pushed out. Hooked up the laptop to ECU and fired the car up everything looked ok until I noticed the wideband O2 the ECU uses was stuck at 14.7 AFR it didn't matter what I did on the fuel table or learn cells the AFR stayed stuck. It is the original sensor I've been tuning on for 8+ years. Easy fix I have a spare, I put that on the header and fired the car up and looking at the laptop the AFR was stuck at 11.0 AFR in the idle zone but would read right with some throttle opening. I'll pick up a couple spare O2 sensors now but I'll run it with the current one until this engine blows or whatever it's fate may be.

 

[WarWagon]

Finally got the Buick out this week for a confirmation test. The trans needs to be freshened up, it's been 5 years but the engine is strong. So a pause on this until I can get the trans freshed up, videos of my adventure today:

https://youtube.com/shorts/BuQW4aFB910?feature=share

https://youtube.com/shorts/Fu7AoPdO0O0?feature=share

 

[AnnyCrooker]

Very good website. Everyone can solve car-related problems here.

 

[b4black]

OK, first car is back on the road, and I think I can definitely say I'm going the blow through carb route on the second car.
If you were starting fresh, what carb and intake would you choose?

Some progress finally! Rebuilding an engine was going to take me way too long. I picked up this long block from a friend that upgraded to a stage 2 motor. '85 block, Champion aluminum heads, roller cam. Ran in the 10's.

To that, I bolted on some junk pats to mock it up. '87 Turbo & downpipe. Weiand intake, Champion AC delete bracket and '87 alternator & PS pump. The stock HEI distributor manages to just fit. I think this will work well.

Next is a pick a carb. Looking at a Holley/Demon carb for boost and E85.

And a fuel pump. I wonder if I should go with a in tank pump and hot wire kit like an 87 GN?

 

[ShawnR]

What kind of fuel pressure can a carb handle? I was going to do that as one of "pre-upgrade" steps, but couldn't find a FPR that would go below 20 psi. I guess I always assumed that anything over 8-9 ish would push past the float valve.

 

[WarWagon]

The carb's needle/seat can handle any increased fuel pressure but while only in boost, otherwise it floods out quite easily. Carbs see up to and over 40 psi fuel pressure while on boost more in some cases. In the past I had 32psi fuel pressure on a Demon carb, base fuel pressure is 7psi then 1:1 regulator matches boost psi which was 25psi then.
Knowing what I learned and all the issues along the way with a "big" number. Small works here very well, 600cfm MAX ideally 500 cfm is it.
Previously my 800cfm carb is 300cfm too big, it worked but with crutches and deminished drivability.
Any fuel system then handles E85 will be good regardless if it's a pusher in tank pump or an inline pump.

 

[b4black]

Knowing what I learned and all the issues along the way with a "big" number. Small works here very well, 600cfm MAX ideally 500 cfm is it.
Previously my 800cfm carb is 300cfm too big, it worked but with crutches and deminished drivability.
Any fuel system then handles E85 will be good regardless if it's a pusher in tank pump or an inline pump.

Looking at Holley's website, this is the smallest CFM they have for blow through:

https://www.holley.com/products/fuel_systems/carburetors/street_strip/parts/MAD-650-BT

 

[WarWagon]

Everything on the shelf will be calibrated for a v8 for sure. Holley, CSU and others will build you the carb you need, it's easy to do yourself too.

 

[b4black]

I'm getting a 550 cfm 4150 Holley carb setup up for blow thru and E85. What bracket(s) would you recommend for hooking up the accelerator cable and transmission kickdown cable? I don't see anything listed specifically for a THM350 trans. (The stock brackets for a draw thru aren't even close to working.)

 

[WarWagon]

Hi Rich. I use this myself on the Buick:

https://www.summitracing.com/parts/sum-g1514

But this really is a generic part, Spectre, Mr Gasket and others all have copied and sell this same bracket.
This one let's you adjust the kickdown and throttle cable mounts on the bracket to operate best.

 

[ek02]

Sent you a PM Rich about the Edelbrock 8036 bracket.

 

[b4black]

Thanks! Autozone actually stocks the Spectra version of the Summit bracket at local stores. (Amazon has it for $10!)

The Edlebrock bracket looks good too.

I just got off the from with Holley and they suggest this:

https://www.holley.com/products/fuel_systems/carburetor_components/brackets_and_linkage/parts/6039

Odd thing is that each of these brackets puts the transmission cable further back than the accelerator cable and when I look at the Q Jet bracket, the trans cable mount is in front of the accelerator cable mount. I'm guessing there will be some trial and error. I ordered the spectra part of amazon - for $10 it's a good (and cheap) place to start.

 

[WE2Regal]

If your using a Holley, I prefer the bracket from Holley that bolts to the rear of the carb. I don't recall the part number, but with minor modifications it can also be used on a Quadrajet. Holley part# 20-100 maybe?

 

[b4black]

Holley lists 200+ items on their bracket page.

20-100 is listed for 4011 carbs
20-95 is for 4150 carbs using the 700r4 transmission. One review on Amazon said it works with the 350 trans. I like the looks, but it's non-adjustable. It does put the trans able in front of the accel cable.

https://www.holley.com/products/fuel_systems/carburetor_components/brackets_and_linkage/parts/20-95

 

[WE2Regal]

Rich, why aren't you using a throttle cable bracket from an NA 3.8 or 4.1? Either should bolt to that Weiand intake. That would take all the guess work out.

 

[b4black]

The car is a factory draw through turbo V6, so the current brackets are wrong and the throttle cable is too short. I'm sure I'll come across a NA set up eventually. I'm not sure if the linkages on the carb are in the same places between the Qjet and Holley. It would be great if they work.

I've always stuck with factory carbs, so this is new to me. I miss the days when every junkyard had a bunch of NA regals to pick parts off of.

 

[WarWagon]

This week is supposed to have low single digit and negative temperatures and I nearly forgot only water is in the cooling system. I promptly drained the water out of the nice 109 block jacket drains.

https://photos.app.goo.gl/ztKV7jJnrbeJY2d26

My garage space is still trashed from LS swap stuff and hoarding parts for my new daily driver.