Finally getting started now that it is warmer

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kkeith1986

kkeith1986

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I had an unexpected day off today so I decided to get a little work done. I got the intake manifold and exhaust manifold flanges mocked up. I am hoping I can atleast get the piping tacked together next weekend as long as my welder is free.

I also started the Hangar blow through modifications on the two barrel. Right now it is just taken apart. I will mill the choke horn off sometime this week and get the power valve holes drilled out a little bigger as soon as I get a pin vise. I also will epoxy up or jb weld everything that was recommended.
 

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Looking good neighbor! Like you, I have been waiting for the weather to warm up a bit...I have a big time case of cabin fever.

Pat
 
kkeith1986 said:
Exhaust holes on the flanges are 1-7/8" x 1-1/4"
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holy christ those are way to big! my ports on my race motor are only 1.45x1.15! and that with a .110 raise port! i have 1 5/8 tube headers which i think are to big even, even with big valves i think slants need 1 1/2" step headers...
 
This is just the size of the flange opening. Inside tube diameter is just under 1-5/8 and is also going to be a log style manifold which should fit in the exact location of the stock manifold. With the turbo I don't get the advantage of long runners.
 
kkeith1986 said:
This is just the size of the flange opening. Inside tube diameter is just under 1-5/8 and is also going to be a log style manifold which should fit in the exact location of the stock manifold. With the turbo I don't get the advantage of long runners.
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no but there are discussions as far as equal length tubes for having even pulses on the turbo... im trying to figure out how your stretch that 1 5/8 tube to an almost 1 3/4" opening...
 
All I am doing is ovalizing the tubing and making it fit. You are really thinking way to much into my manifold. It's a log manifold and its a very simple design. It is no where near going to be a race motor nor am I looking to run an insane amount of power. To be honest if I can get 175hp and 230 ft.lbs out if I would be more than happy. I might one day build a motor and do it the right way but for now I'm just having fun with it.
 
Looking forward to watching this fun build and hopefully learn something on the work you do to the Carb.... Enjoy this cool build :cheers:
 
If my buddy calls tonight and says that he is going to be around in the shop then I will be putting the carb on the mill to get rid of the choke horn. I am assuming he will be in the shop since he got his funny car frame back and race season is approaching very fast.
 
Don't drill the power valve holes until you get it running, I did and ended up having to plug one while running at 6 lbs of boost. at 10 lbs it was fine, but I was worried that 7.25 rear couldn't handle it as 10 lbs smoked the first clutch.
 
Thanks for the advice. I have been trying to decide if I was going to drill it one size up. I will wait till after I get it running for now. What size carb are you running and what jet sizes do you recommend for a 350cfm 2 barrel?
 
I found a 1.5 pipe can almost be shaped into a rectangle that will fit, but alas it was just a tad too small, I went with 1 3/4 pipes and made them squarish in a vise and still had a little overlap at the flange, perhaps some AB epoxy to smooth out the step...
<<<<< CORRECTION >>>>>>>> mine were Aarons intake flanges...my bad. But the intake ports are larger than the exhaust ports on a slant....
 
player1up said:
Don't drill the power valve holes until you get it running, I did and ended up having to plug one while running at 6 lbs of boost. at 10 lbs it was fine, but I was worried that 7.25 rear couldn't handle it as 10 lbs smoked the first clutch.
Click to expand...
Could you drill a tapped hole into the PV restriction area and screw in an idle screw to alter the PVCR area? Not looking at mine but I drilled mine out to .076 and perhaps I went a little overboard. I can always plug and redrill but adjustability would be very cool with a wideband O2. With a fixed PVCR hole you could adjust with the wastegate..too rich, just add a few PSI!
 
pishta said:
Could you drill a tapped hole into the PV restriction area and screw in an idle screw to alter the PVCR area? Not looking at mine but I drilled mine out to .076 and perhaps I went a little overboard. I can always plug and redrill but adjustability would be very cool with a wideband O2. With a fixed PVCR hole you could adjust with the wastegate..too rich, just add a few PSI!
Click to expand...

There are a few companies that make jetted ones, but the "jet" is tiny. The adjusting screw is an interesting idea, but not sure how that could be accomplished because it's all internal.

The issue with going too big is that it will run way too rich right when the power valve opens then and only get a little better on the top with boost. The idea is that even though the hole is a set size, pressure increases with boost, therefore flow should also increase. So just adding boost isn't really the answer.
What I noticed is that it only works that to a certain extent. It's the whole transition from vacuum to boost that seems to be a problem area... I am in no way an expert, just stating what I've noticed on my car and remembering some of what I've read.
There's just a lot of testing / tuning involved with balancing main jet size, power valve restriction size and power valve open time based on driving conditions.

Go too big on the power valve and it'll bog just before boost comes in ...that's what mine was doing and I had to close off one of the ports cause I apparently went WAYY too big...lol
 
Looking at the Metering block tells me there is a possibility to be able to adjust PVCR size. Drill PVCR's out from the front as described but drill them back at a 45 through the main well, not out to the sides as drilled by holley. The drilled hole will be somewhat ovaled but will now be coming out the front of the metering block right above the main jets and the right side between the accelerator pump passage boss. You can now tap these to short tipped Holley 4000 teapot curb idle adjustment screw pitch (8-32?) on the front side of the block
489-2_thumbnail.jpg
and screw in a curb idle screw and effectively fill the PVCR with the tip of that screw. Run screw in and the PVCR is closed or made smaller, loosen the screw and the PVCR window becomes larger or bigger. Youll have to adjust these with the bowl off unfortunantly but it looks feasible. Have to check it out on a spare block I have. Hey, a new patent to sell to Quick Time Fuel! Just outside of #15 in lower diagram, screws will be coming out at a 45 in either direction....

MeteringBlocks-Holley.jpg
 
Just drill your pvrc to 1/16 and jet according I'd say start with a pair of 72 also remember you have the accelerate pump shot which is fully adjustable by changing from a 30cc to a 50cc then you can adjust your pump cam for different ramp and fuel characteristics but a WIDEBAND is a must.

This is what I use as a quick reference when I'm adjusting and tuning a carb
http://members.tccoa.com/392bird/tuning.htm

Just my two pennies of knowledge
 
Pishta - keep us posted on your idea.

Toad - The stock jets were #62. I was thinking about going up a #70 at first while using a vent bowl extension. (The turbo carb guys swear by the vent extension) I am also keeping the accel pump stock for now. I already have a wideband and will be doing most my tuning based off that.

My biggest concern right now is the distributor. I really want to just run the distributor without a boost reference. I have been talking back and forth with a distributor tuning company and they are saying with my low boost numbers, getting rid of the vacuum advance and recurving it would be a good option. They suggested 14 degrees to start and having it max out to 26 degrees. He said that he has worked on a few slants and that he has noticed that they dont like a lot of advance. He also suggested that I be at full advance by 2600 rpm because its a low revving slant.

I know going with a programmable ignition or a boost referenced ignition would allow a lot more tuning. I will eventually go that route when I start creeping the boost higher but that is a long ways away. Right now I will be happy with 5-6 pounds. I have a lot of limiting factors with boost.
 
thanks for the link and I might have to give that a try before I send my distributor out to be recurved. Is locking out the distributor easy?
 
I ran a modded dizzy. Initial advance was 8° BTDC total advance was 18° and I hacked together a vac/retard pot from a turbo volvo, just cut the end off of the arm and welded the stock advance arm onto it. I think I still have it kicking around in the garage. I'll see if I can get some pics up. 14° seems a lot to start with.
You're right on with the vent tube extension, I was able to get away with a 68 ( I think ) once I did that. 8lbs at full throttle running right at 11.2 AFR by the time I was done tuning it.
Pisha, that adjustable jet thing is some food for thought...wish I still had the turbo setup going to try that out... :(
 
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