Performing Honda K24a3/AST5 6spd Conversion
- Thread starter lookforjoe
- Start date
PaulD
Paul Davock
Your welds are gorgeous, you have come a long ways since your early exhausts. I wish I could weld that well.
lookforjoe
True Classic
I wish those were mine - The header itself is pre-fabricated, I'm just modding the runners to align with the chassis - the RAM area is not my work.
These are my welds - sleeve joints definitely make for ugly welds (for me anyway) - I have a much easier time with butt welds, however that would have been way to complicated in this case, too many potential moving parts to stabilze
all I got done after work was the forward extensions & the slip joints
lookforjoe
True Classic
So, I didn't measure them before cutting to check if they were equal, however with the modified runners, 2&3 are 30" and 1&4 are 28". I hope the variance is not problematic, not much I can do about it. When I make the 2-1 runners, I will likely have one runner shorter than the other by a couple inches. The existing 2-1 runners were about 5' - not sure if there any benefit in trying to extend that length if possible?
Because of the angle of the rear valance, I may need to drop them down & forward something like this (which will make them closer to 8-10'):
Because of the angle of the rear valance, I may need to drop them down & forward something like this (which will make them closer to 8-10'):
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lookforjoe
True Classic
After futzing with the previous ideas, I determined dropping the runners would end up too low - below the rear valance & close to the bottom of the crossmember.
So, it's gonna be more like this:
Lower pipe will need a short 'pie cut' from a mandrel bend - likely end up about 3" longer than the upper runner
So, it's gonna be more like this:
Lower pipe will need a short 'pie cut' from a mandrel bend - likely end up about 3" longer than the upper runner
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lookforjoe
True Classic
Indeed! - These are also only 2" - the rest of the exhaust is 2.5", the recommended (for K24) 3" would never work.
lookforjoe
True Classic
Header is mostly assembled at this point. Next I need to rework the entire exhaust around it. I would like to keep a cat in the system, so I will probably have to do a whole extra loop to the right side & back again
I have to accept whatever penalty in flow the uneven lengths will cause - just no way to route it otherwise.
Runner for 2-3 into the 2-1 collector is 3"(!) longer than the other.
I have to accept whatever penalty in flow the uneven lengths will cause - just no way to route it otherwise.
Runner for 2-3 into the 2-1 collector is 3"(!) longer than the other.
TonyK
True Classic
Hussein, did you consider using donuts for tighter radius bends? This could solve some of the tight turns required in a small space.
See this link https://www.ebay.ca/itm/353408760359?hash=item5248cdba27:g:eDcAAOSwtNFdXaI6
There are a lot of different sizes to choose from. Just cut the section and weld in place.
TonyK.
Grimsby Ontario Canada.
See this link https://www.ebay.ca/itm/353408760359?hash=item5248cdba27:g:eDcAAOSwtNFdXaI6
There are a lot of different sizes to choose from. Just cut the section and weld in place.
TonyK.
Grimsby Ontario Canada.
lookforjoe
True Classic
Thanks Tony! I seem to recall now pics where you used this - I ordered one to play with. That may make it easier to run a U & add the cat in the lower DS area.
Rodger
True Classic
Looks wild! You really should figure out how to create more clearance where the pipes come through the opening above the cross member. I thought I had plenty of clearance (about 1/2”) to the crossmember with mine, but when I took it apart to modify it, I found that there was contact with the crossmember at some point, probably with acceleration. I ended up using a small sledge hammer to indent the crossmember to give me another 1/4” of distance. Yours looks really close top and bottom.
lookforjoe
True Classic
Yes, thanks for the input Rodger - I was thinking about ways to address that - with the old setup the V Band clamp was knocking the rear crossmember edge. I am going to use stiffer poly mounts recommended by Brayden - however, I think I will notch the rear edge & the upper inner left side cross brace to allow for rebound. I can't just whack it as mine has a SS plate reinforcement across the top surface of the crossmember, in addition to the external bracing we added on the rear vertical surface.
lookforjoe
True Classic
More fiddling around today
This mandrel bend will be cut to feed into the muffler on top
What will make this possible is this: Tightest mandrel bend "U" available (Thanks, @TonyK !). 7.5" outer radii will be perfect to feed the header collector into the cat.
Muffler will be angled in space above collecotr
smaller OD Poly mount has more clearance off the header. I'll still put a heat shield back
clearance off the crossmember
So... I made some cuts & reshaped the crossmember & upper crossbar. Will be welded later
checking clearance after
Pretty sure I'm good now. All will be cleaned up & painted after welding
The header has to be pivoted thus to remove/install. So, the body support has to be a removable section no matter what
This mandrel bend will be cut to feed into the muffler on top
What will make this possible is this: Tightest mandrel bend "U" available (Thanks, @TonyK !). 7.5" outer radii will be perfect to feed the header collector into the cat.
Muffler will be angled in space above collecotr
smaller OD Poly mount has more clearance off the header. I'll still put a heat shield back
clearance off the crossmember
So... I made some cuts & reshaped the crossmember & upper crossbar. Will be welded later
checking clearance after
Pretty sure I'm good now. All will be cleaned up & painted after welding
The header has to be pivoted thus to remove/install. So, the body support has to be a removable section no matter what
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lookforjoe
True Classic
Hey Rodger - do you have an invoice with a part number for the specific unit? I can't find one on the website that matches your description
Nevermind - I found it later in the thread - STL25.
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lookforjoe
True Classic
Only had about an hour today - so I got the 3 cuts welded - not pretty, however it doesn't matter. I'll clean them up & paint with the stone chip & topcoat.
lookforjoe
True Classic
Painted the welded areas yesterday.
Mandrel bend and muffler came today, cut the mandrel & welded it to the flex coupler that will attach to the cat
Have to figure out how I'm going to re-introduce the cross plate
cut all off the underside except a lip I can use for welding
I bought some 1.75" DOM tubing from Summit - I was thinking of full cross braces, however I think I will make it insertable, with securing plates/tabs
Mandrel bend and muffler came today, cut the mandrel & welded it to the flex coupler that will attach to the cat
Have to figure out how I'm going to re-introduce the cross plate
cut all off the underside except a lip I can use for welding
I bought some 1.75" DOM tubing from Summit - I was thinking of full cross braces, however I think I will make it insertable, with securing plates/tabs
lookforjoe
True Classic
Only spent a short time on it today - just cleaned up the wiring to the various solenoids and sensors that are now too close to the header. Extending the wire to the oil pressure sensor, routing it behind & under. Heat sheathing added on that.
