Project: Hot Rod Cherokee

[Shark]

"black and tan", nice.

gotta love the pick'n'pull. im headed into the local yard in just a bit myself. got a laundry list of parts. also gonna see if theyve got a fender for Muad'Dib.

any updates on the turbo install?

[1bolt]

Too many other things going on at the moment. I probably wont work on it again until next week. But I'm doing a parallel project which is a second version of my home brew Cowl induction hood. it has some turbo heat provisions. The first version of my hood will appear here soon.

Anyway for a Turbo I've basically no choice but to solve some heat issues before it is functioning and generating even more heat. Especially considering I'm Turboing a stroker that has previously had some heat related ping, and a far from Ideal CR around 9.2:1. I've got several ideas on how to deal with it, from a head swap with ported Chambers to lower my CR. To various injection schemes.

I also may be looking for a 23 spline AW4 here soon. Mine is over 230,000 miles and just started getting the occasional slip and grab at WOT... Which is a scary sensation.

[Shark]

what heat issues are you experiencing?

how much boost you plan on running? intercooler?

[1bolt]

however much I can get away with 5-6 PSI to start, because I have BOV's from a Supra and an Eclipse that will vent around those relatively safe levels...

Heat issues are the normal XJ variety... it's damn hot in an XJ's engine bay so I need fresh outside air into the filter at the Tubro inlet. Fresh cool air over the intercooler and I need to vent the already hot air even without a turbo so it's even more important to vent it after the turbo starts heating things up.

I think I have a workable system but it's only just started. I guess we'll see. I do know that one of the very few sucessful home brew XJ tubo setups written about on NAXJA (the only one I've seen) was eventually scrapped because of reliability and engine compartment heat problems. So I intend to address that going into it.

[Shark]

I'm somewhat past mockup it's not mounted yet so don't worry. I'll let it unfold in the thread. I'm playing with two different Garrett clones. One (which would probably boost off idle) is a T3 .48 hot side .42 cold. The other which I expect to keep mounted is a chinese T04E .68 AR exhaust (56mm wheel) and .50 AR compressor (48mm).

did you pull these from the junkyard or buy them aftermarket?

[Shark]

however much I can get away with 5-6 PSI to start, because I have BOV's from a Supra and an Eclipse that will vent around those relatively safe levels...

Heat issues are the normal XJ variety... it's damn hot in an XJ's engine bay so I need fresh outside air into the filter at the Tubro inlet. Fresh cool air over the intercooler and I need to vent the already hot air even without a turbo so it's even more important to vent it after the turbo starts heating things up.

I think I have a workable system but it's only just started. I guess we'll see. I do know that one of the very few sucessful home brew XJ tubo setups written about on NAXJA (the only one I've seen) was eventually scrapped because of reliability and engine compartment heat problems. So I intend to address that going into it.

the heat issues are easily fixable as you know with hood vents, but a home brew "ram air"(or modified blinkers) would be better. i was talking about over in the advanced forum. more air in,more air out. no heat issues. should solve the heat issue all together.

why cant i find decent hood vents at my JY? only ones even close so far have been off a 85 or so prelude. might go back and get em but didnt like how they mounted.

[1bolt]

Teaser:


That's some initial work on my 2nd hood project

[Shark]

not too many people running louvers... i like it.

[aaronkeiser]

Why not just cut a hole for the louvers, drill holes in the louver, then tighten it down to the hood with sheet metal screws? It would be easier and less time consuming then welding and all the smoothing of welds. Easier to clean up, paint, and make perdy.

[1bolt]

not trying to sound cocky but you know that saying "if you have to ask... "

Seriously you know how much bondo you would need to cover sheet metal screws and make it look perdy? It wouldn't look perdy. It would be so thick that it would crack off very easy. The heavier you go with body filler the easier for it to crack off.

The "proper" way of doing it is via welding, I'd go so far as to say the ONLY way to do it is with welding. Unless you are a professional glass layer then okay there's another way, but making this hood out of fiberglass would require making it first the way I am making it (out of metal) to use as a mold.

There's a lot more to this hood than just a small section of louvers.

Anyway check my next update which I wasn't going to do tonight, but since the subject came up...
[edit] Never mind its too late, I'll get to it tomorrow maybe, but my first cowl induction hood should illustrate my point.

[1bolt]

I wanted some way to pull cool air into a less restrictive intake tube and filter that didn't involve the factory air box. I also like the agressive looks of a Cowl induction hood, and the One Quadratec started selling around this time looked cool, but was more money than my Wi... er I mean I wanted to spend especially after the cost of painting it. I'm also a fan of shows like American Chopper, etc. which feature sheet metal fabrication. So I'm not kidding when I say this was my very first sheet metal fab work and I used a $119 flux core Mig from Harbor Freight.

Started with the hood off a parts Cherokee, masked the lines I thought looked best. This write up makes it sound quick and easy but I probably days just figuring out where to cut, moving masking tape around. I sarted with straight lines and didn't like the lines not agreeing with the factory lines so I ended up curving the line to mimic the factory ones:

Once you cut these (don't go all the way through the supports leave them be) you cut the cowl area underneath and leave the nice factory rolled edge:



In the above pic you can see the panel glue the factory uses, it is all over the place under the structure where the skin meets the frame. I cut through it using a sharp putty knife. Not difficult at all. once I was 100% sure I had every single bit of glue cut through I raised the metal skin up and used a couple pieces of wedge shaped metal to form supports in the very front of the hood, too hard to take a pic of them, but if you think of a wedge between the frame and skin in the first 5 or 6 inches of the front you'll get the picture.

I made profiles and matched them to each other, and I put supports at the new cowl opening, welding them to the frame and the bottom of the rolled lip. This pic shows both the side profiles and the cowl opening supports:



Around here I got cocky and made some rookie mistakes that were bound to happen. In the next pic you can see the welds are "stitch welds" that is spot welds spaced out at random to minimize the effect of heat build up. Too much welding in one place on thin sheet metal equals instant warpage and wavy panels. The next pic shows the damage I sanded the paint far away from the wavy areas so I could feather the body filler out but the wavy places pretty much follow the contours of the paint sanding line. I learned a lot of stuff on this hood, most of it the hard way...



Like how much bondo it takes to hide overly enthusiastic sheet welding



And how much sanding follows all that bondo spent a lot of time sanding. using a body file (rasp) to knock down the bumps from application, followed by 40 grit. Once I got the waves out I skimmed it and followed with 220, then primer



Primer was a relief final sanding was 400 grit followed by Sherwin Williams 2nd Dimension Auto gloss primer (primer sealer):



Then a single stage color coat (color and wet look hardener). This stuff was expensive pro quality auto paint. On hindsight I wish I had gone with a base clear two stage paint (which is even more expensive and probably why I didn't). The results as seen on my Comanche are worth the extra money. Base clear is actually much easier to paint with, the flash times and adhesion "window" where you have to put the clear on before the color gets too cured (or you get poor adhesion) are intimidating to read about. But once you do it it's like "why the hell was I was worried about that?" I painted in a shop with bugs flying around the lights, a few of which made tracks on the paint. when it was all cured up though the minor imperfections weren't all that noticable.



More later.

[Shark]

looks f'n great man. when you gonna put that thing on?

[Muad'Dib]

ill buy one wanna sell?

I wish i could paint .. my heep needs a paint job. If i could paint then id be less reluctant to buy different colored fenders also. Ive just barely gotten better with a damn rattle can!

[fedrusion]

Looks amazing.

How has the paint held up I have herd that paint work over flux core welds dosnt fair to well.

[Shark]

he does have bondo and primer over those welds. that should help.