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No no sleeve. I’ve seen you post that same comment before and I just can’t understand what’s going on. As far as I know Rochester only made one version of the TB but maybe maybe something changed during its life cycle.
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Originally Posted by BuccaneerView Post
It's NOT BS! If done properly you can go farther than that. Mine are bored 2.13" and 53mm is only 2.08661". Mine are NOT sleeved at all and done professionally by my machinist locally. Ben73 in Australia has his TBs bored to 2.20" without issue.
OK Tom. You'll have to show me how to keep machining out a wall that isn't there any more. Tell us what "properly", is?
Mmmm... I guess "properly" would be using a Bridgeport end mill in a gig made for boring TBs dead straight when we were doing them back in the DCS days. We did a lot of TB boring. I watched my machinist do mine with NO issues. What can I say? No glue holding mine together though.
Core shift? IDK....a boring bar is a pretty precise tool; it's used to bore cylinders. Once you find center, not sure how to screw it up, but something is "up"....If Ben got 2.2" w/no breach, that is impressive.
I agree that I think all GM 1 bbl TBI's are the same thing.
Core shift? IDK....a boring bar is a pretty precise tool
when using the right chip load and DOC. Best tools in the world are worthless when used improperly. Just like a paint job, machine work is about prep too.
One thought. @Buccaneer when you said some strange phenomenon occurred where flow stopped on the bench on the stocker... would you care to elaborate? I have a feeling it is to do with harmonics in the runner length but I'm curious if you recall any of the specifics of what you think caused it?
So what is looking like will happen at the moment is a decent chunk of my at depth porting will come from removal of material from the side walls. I am awaiting my burrs which should arrive tomorrow. I plan on powerwashing up the base tonight and also one thing I forgot, I will be removing the egr passage as per this link. I have a blockoff plate already so it doesn't matter and my build has so much overlap egr is pointless. And no crossover in the heads.
Also as far as keeping things fair... I think 1 pull with the optimized tune for the stocker is in order that way there is a real WOT pull to show how AFR changes. Then I will alter the VE tables and retest. I feel that is good as it will closer represent how the ecm can attempt to compensate.
For all purposes PE afr will be the target in tune... as of now I have it set at 12.8 as the car seems happy there. On the dyno that could change.
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Originally Posted by 84 4+3
One thought. @Buccaneer when you said some strange phenomenon occurred where flow stopped on the bench on the stocker... would you care to elaborate? I have a feeling it is to do with harmonics in the runner length but I'm curious if you recall any of the specifics of what you think caused it?
So what is looking like will happen at the moment is a decent chunk of my at depth porting will come from removal of material from the side walls. I am awaiting my burrs which should arrive tomorrow. I plan on powerwashing up the base tonight and also one thing I forgot, I will be removing the egr passage as per this link. I have a blockoff plate already so it doesn't matter and my build has so much overlap egr is pointless. And no crossover in the heads.
Also as far as keeping things fair... I think 1 pull with the optimized tune for the stocker is in order that way there is a real WOT pull to show how AFR changes. Then I will alter the VE tables and retest. I feel that is good as it will closer represent how the ecm can attempt to compensate.
For all purposes PE afr will be the target in tune... as of now I have it set at 12.8 as the car seems happy there. On the dyno that could change.
Unfortunately I do not readily have the data to give you, but may have it here somewhere, that was 12 years ago. What was happening is in the corner runners as the charge came down, it would hit the flat floor of the manifold and have to make a 90* turn kind of to go into the runners. This created a type of runner reversion vs. ramming the charge into the runners. We made the changes to the floor of the Renegade which you can easily see so that the runners are canted up and with the bell lip it rolls the charge into the runners. We also changed the cross sectional area and tapered the runners to the ports to give the ramming a boost into the heads. I hope this helps a bit.
Last edited by Buccaneer; Jul 10, 2020 at 05:15 PM.
Unfortunately I do not readily have the data to give you, but may have it here somewhere, that was 12 years ago. What was happening is in the corner runners as the charge came down, it would hit the flat floor of the manifold and have to make a 90* turn kind of to go into the runners. This created a type of runner reversion vs. ramming the charge into the runners. We made the changes to the floor of the Renegade which you can easily see so that the runners are canted up and with the bell lip it rolls the charge into the runners. We also changed the cross sectional area and tapered the runners to the ports to give the ramming a boost into the heads. I hope this helps a bit.
When you're done, I think I'd "copy" Bucc's idea and mix up some mold-able epoxy and lay a bead of it around the perimiter of the runners' mouths, to create a nice "bell mouth" radiused inlet.
When you're done, I think I'd "copy" Bucc's idea and mix up some mold-able epoxy and lay a bead of it around the perimiter of the runners' mouths, to create a nice "bell mouth" radiused inlet.
I was considering it however, due to the height difference inside the plenum I do not believe it would have the same effect.
You could also make a lid spacer to give you more plenum volume and space between the runner mouths and the lid.
Disclosure: When I had my 400 CFI (Cam/headers/exhaust, ported intake/lid) I made a 1/2" plenum lid spacer out of Corian (sp?) and it made absolutely zero discernible difference; SOTP and/or at the track.
Now mind you... a 1205 (pictured) is still slightly smaller than the port on my head... I just don't think this would seal if I hog it out any larger...
What was happening is in the corner runners as the charge came down, it would hit the flat floor of the manifold and have to make a 90* turn kind of to go into the runners. This created a type of runner reversion vs. ramming the charge into the runners. We made the changes to the floor of the Renegade which you can easily see so that the runners are canted up and with the bell lip it rolls the charge into the runners. We also changed the cross sectional area and tapered the runners to the ports to give the ramming a boost into the heads. I hope this helps a bit.
