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You definitely need a ball burr on a longer shaft to get around the plenum corner. I could have probably done better on mine in retrospect (as I spent more time with the I/H's). That said, it seems the top plenum flows better than the i/h's stock so with no injector hump and other odd geometries, maybe it will be less work to achieve the flow you need to match the other part.
I would maybe take a trip to horrible freight or check ebay for a good used air grinder with a rubber grip coating so you won't freeze your hand. I chose to use the air compressor at work over the weekend to save my neighbors from having to hear it run for hours on end.
I like the electric Mikita. Lots to hold on to and you can set the speed and forget it. The air tools are loud and require steady hand pressure to maintain desired speed which I find very tiring. A foot pedal switch for emergency power OFF would make the Mikita ideal.
The round burr would deff help but I worry about going to deep with it no longer having a line of sight once one starts grinding around corners and stuff.
The Makita has a viable speed dial on it. I just set it and forget it. The pedal is more for safety. I am ordering some ball shaped stones and burr to help remove some material in the 90 degree transition. Very hard to do with an oval burr. I am still on the fence regarding the IH's. The primaries entering the head are only about 32mm. Not sure if I should just taper down to 32mm and remove most of the injector boss or open up to maybe 35-36mm. This will require some port matching on the head as well. My 95 was opened up to nearly 38mm . I port matched the head with out issue being sure not to get to close to the coolant port. The injector housing has coolant cavity and crank case ventilation cavity as well. I have been measuring wall thicknesses as I go and have been seeing initial thicknesses in the 0.15 to 0.25 range. I am trying to go no thinner than 0.10". Have hit 0.08" in one particular spot on the intake plenum. Basically it is the inside radius of the turn into the injector housing. It is thin there to begin with starting at about 0.12". Need to focus on the larger outside radius. Lots more "meat" to work with there but it is also more work. I have done an OK job of maintaining center-line but perhaps that is what differentiates someone who has done a lot of these from the first timer. The plenum is challenging because of the turn. One needs a good eye for symmetry. I have 4 ports about done minus some clean up. As soon as I get one side done, I will check the flows values.
I wonder if it is worth opening up the throttle body to 63mm. After all this work I would want to optimize the effort but it costs $$$
I was just pondering the same thing since mine is apart and doing a full port job. Marc says it might be good for 8hp but the $600 for the 8hp is what's holding me back. I might wait till next time if I do cams, or build a stroker down the line...
I was just pondering the same thing since mine is apart and doing a full port job. Marc says it might be good for 8hp but the $600 for the 8hp is what's holding me back. I might wait till next time if I do cams, or build a stroker down the line...
The real cost in doing a larger throttle body on a speed density fuel injection system is all the work tuning it to not stumble or run lean when you open it up. I would for sure do it on a rebuild to a larger displacement engine.
If you are still going to run stock exhaust manifolds- no way.
Take the 600 put it in your pocket
Big TB are overrated most times.
Everyone in sales will tell you have to have one or else-
If one could track down the correct over-sized throttle plate, I bet a decent machine shop could open up the bore for less money. My guess however, it must be harder to do than it appears. The going rate for this work seems to be in the 500+ range. Because it likely requires special tooling and equipment to do, those who do it, likely sub out that part of the work which would add to the cost for sure. My 95 has a 63mm throttle body from previous owner. I am tempted to remove it, blue print it and see if I can find a local shop that can do it just for ***** and giggles.
Regarding the larger throttle bodies, I suggest you talk at length with Marc Haibeck about them. He always installs them on his high horsepower packages when the exhaust and heads are opened up for higher air flow. And I believe there is a certain amount of art involved in making them work right and in fine tuning the engine. --Bob
I understand the dial thing but once you go to a pedal or if you ever use air being able to adjust that quickly youll get spoiled.
A-men!
Its all about control! I liked the electric Makita constant speed too, but w/o instant cut-off or instant speed control, I found it was not the best solution (for me). I wanted immediate cut-off, as (especially) the long stem burs are tricky to control and can easily "hook" on the aluminum and result in rattling around inside the runner - punching holes where there were none just an instant before, before one can react! (Ask me how I know!)
I ended up with (and liking very much) an air-driven Snap-on air tool die grinder, after going through a couple cheapie tools from a "big box" discount store. (They probably would have been OK for occasional or light use. But, 2 hours+ per runner x 32 x 3 (plenum, IHs, and heads) shelled out the cheapies pretty quick.
Marc Haibeck demonstrated to me how to use the tool.
He held the tool with both hands, with his elbows locked to his sides, and the air hose passing from the tool, over his shoulder. By using his hips to rotate his upper body, he could move the burr smoothly and precisely in a circle around the inside of the runner. With obvious practice, he is able to "cut a runner" in a fraction of the time it took me, and yet maintaining complete control - most of the time, anyway.
The Makita GD800C is the one with the constant speed set control I think was the one mentioned by the OP. I ended up leaving it with Pete, as he prefers it over air tools (I guess).
Yes, I had it hook on me early in the process. I made two mistakes, the burr was too long and the speed was too fast. It bounced around uncontrollably inside the plenum bore. As I pulled the tool from the bore, the burr shaft actually bent 45 degrees. The tool is now widely vibrating to a point where I could not get my hand to the shut off switch. After what seemed like forever, I managed through brute force to hold the tool steady enough to slip my hand down to the switch. This could have ended very badly for the plenum and/or me. The plenum was roughed up a bit but cleaned up fine and the bur was still straight enough to use after I cut the bend off the end. With the correct length burr and cutting at the slowest speed, it seems controllable now but no doubt slows the process down. I added the non-latching foot switch for safety. I can see where the air tool would be the better choice for experienced users and more safe. For a person who knows when they can user faster cutting speeds versus slower on the fly, air is the way to go for sure. If I have another hooking episode, I may switch to air for the cutting burr and the Mikita for finishing. May give me a reason to purchase a new compressor.
After trying both air and electric die ginders I now prefer aheavy duty flex shaft grinder. Plenty of torque for swinging large hogging burrs and excellent control for the precision work.
After trying both air and electric die ginders I now prefer aheavy duty flex shaft grinder. Plenty of torque for swinging large hogging burrs and excellent control for the precision work.
Those are some serious tools. My guess is you do this more than just for your own cars. I also purchased a set of deep throat verier calipers. Would be perfect if the tips were about .25" long. It looks like you modified yours. Are those ball grinding stones? What are those pieces standing upright behind the tools? Can you provide more info on the flex shaft grinder?
As secondchance said I keep the cross-section cuts of LT5 head handy to remind me where the water passages are.
I use a Foredom K-TXH440 industrial flex shaft grinder http://www.ottofrei.com/Store/Foredo...Shaft-Kit.html
This one uses the heavy duty square drive shaft and corresponding heavy duty H type hand pieces.Control wise I much prefer it over air die grinder or larger hand held electrics. With the right burrs it produces precision work. Motor noise is low, mostly drowned out by the cutter. Once you get use to this one you'll find it hard to go back to the others.
Last edited by Jagdpanzer; 02-19-2017 at 09:07 PM.
Damn, those must be very handy to have. I am only planing on opening the and matching the primary on the head to match the injector housing. Only going in about 1 inch or so. I assume this area is OK as I successfully did the same on my 95. I have completed one side of the plenum. I am getting faster at it. My biggest concern is opening up the primaries in the IH's. Can they be safely opened up to 36mm at the head? Can you offer any advice or pitfalls when doing the IH's? Tricks to grinding the primary injector boss? Do you port them mounted flat or do you angle them so the port is vertical? Do you port them from both ends and meet in the center? Lots of questions.....
Damn, those must be very handy to have. I am only planing on opening the and matching the primary on the head to match the injector housing. Only going in about 1 inch or so. I assume this area is OK as I successfully did the same on my 95. I have completed one side of the plenum. I am getting faster at it. My biggest concern is opening up the primaries in the IH's. Can they be safely opened up to 36mm at the head? Can you offer any advice or pitfalls when doing the IH's? Tricks to grinding the primary injector boss? Do you port them mounted flat or do you angle them so the port is vertical? Do you port them from both ends and meet in the center? Lots of questions.....
My expirence is with the later 93-95 injector housings so I'll have to let the other guys who know the earlier injector housings respond.
01-23-2017, 12:51 PM
