1983ZX Conversion

[danj]

In the process of having a 383 Stroker placed into my 1983ZX 2+2. Will be running a 700R-4 tranny and Skyline GTR limited slip rear.

 

Having a problem finding a header that clears the stock steering column (power steering unit). Does anyone have any experience or proven knowledge on this?

[Guest greimann]

I am running a stock cast iron manifold, but I have the steering box type of steering, not rack and pinion. Ross C. has a rack, perhaps he will chime in. He posts regularly.

[Guest super280z]

*crosses fingers* i'm in the process of swapping out the box for a R&P and im using block huggers. i really dont know if it's gonna fit or not. Ross?? speaking of Ross, did you get my check yet?

[danj]

The block huggers didn't work on my application on the steering side so it looks like we're heading into custom fab territory. After reading Grumpy's comments on determining optimum header size I wonder what effect design/shape has on enhancing or diminishing performance when the original manufacturer's design is compromised through custom fabrication just to make things fit.

 

Grumpy, would you like to share some thoughts on header efficiency from both a size and design standpoint?

[grumpyvette]

first thing is Im well aware that getting the damn headers to fit can be a real P.I.T.A. but why you guys don,t just make your own custom headers if you have the ability to weld has me confused, read this,

Ive done it many times and since you have all the tools its not that hard. heres what I do, get some of that plastic smurf tubeing in the 2" dia size and some ceiling hanger wire and some of that hard set constuction isulation foam. now weld 1" stubs of the exhaust tube to the header flange exhaust ports and bolt it to the cylinder heads. clamp the collectors to a 6 foot section of 2x6" wood and jack it up solid under the car (collectors not touching the car anywhere)to position them where you want them under the car, now cut (8) sections of smurf tubeing about 36" long(theres a formula to figure the exact length)slide 4 pieces of ceiling suspension wire in each tube with the ends looped over inside the tube. now startin with the upper inside collector position and the rear exhaust port, bend and fit the smurf tubeing to fit, the next forward exhaust port goes to the lower inside collector port the next exhaust to the upper outside collector port and the furthest forward to the lower outside collector port , once they are all bent to fit shoot the tubes full of hardening construction foam, let it harden and then pull each individual tube off one at a time and have a mufler shop duplicate it in steel tubeing, this method REALLY makes the fit and try time minimal. and assures equal length tube headers.

heres a quick way to figure your true primairy tube length (use 1250f degs(950k) and 5000rpm for race cars, 1200 degs(922K) and 3000rpm for street cars)

 

http://www.engr.colostate.edu/~allan/fluids/page7/PipeLength/pipe.html

 

http://www.prestage.com/carmath/calc_headerlength.asp

or if your really lazy

 

if you want other temps look here,

 

http://www.convertalot.com/downloads.html

 

and the answers in meters (about 39"=1 meter)

 

but if you just use 36" it will just move your tuned rpm level up or down slightly, not enough to make much differance except on a very peaky engine combo in a very light car.and this assumes your tube dia. is the same size as your exhaust port size.(never smaller, slightly larger dia. is ok.)

btw mild steel is much easier to work with than stainless steel.

BTW SMURF TUBEING IS flexable plastic electrical conduit thats normally BLUE and COMMONLY called smurf tubeing by contractors its a plastic version of that metal GREENFIELD tubeing that electrical contractors use but its cheaper and easier to work with, it resembles a canister type vacuum cleaner pickup hose but stiffer, its available at big hardware stores,and electrical supply houses dirt cheap in 10' lengths about $6 each or les you will need (3)

 

 

the 4 wires act like rebar in concrete, the loops keep the wires from moveing in the foam while their incased in the construction foam, the hard plastic foam is what keeps it stiff and no it will not be exact you will still need to tweak it to get it to fit but it will speed up the process of making the tube pattern shapes. just keep in mind that you can buy headers fairly cheaply (under $300 in many cases) for most cars its when you go and get an odd ball combo this comes in handy, like putting a 502bbc in a 57 vette or a 392 hemi in a 63 falcon, or you need headers for a LS1 in you 67 camaro

[Guest Anonymous]

Mr. Grump: Absolutely facinating custom exhaust header fabrication proceedure lesson.

[Guest gprix1]

OK That settles it, I'm doing my own headers. I would guess that you would also want to get them coated (inside and out) once completed right?

[blueovalz]

I built my own headers mainly because of the desire for equal length tubes. I used the Hooker J-tubes and the "rings" that are used to hold sections together while welding. I simply mocked up the steering rod, frame rails, and anything else that I thought would get in the way, and began cutting and fitting. Once you cut a half dozen tubes you will get the idea and hang of it. I can't over emphasize the "rings" that you can get with the tubes that aid construction. They fit on the ID of the tubes, and lightly hold the tubes in position while you tack it all together, with minimal obstruction on the inside. Very nice, but they are more expensive that I think they should be, BUT, they do make the job much easier. After watching all my hard work being oxidized into oblivion (about a year after I built the headers), I decided to have my headers Jet-Hot coated just so I wouldn't have to do it again if I decide to hang onto this car a long time. I never realized how really nice the coating is, and how much cooler the temperatures are during and after shutdown are under the hood.

[blueovalz]

Yeah, the dirt dobber got ahold of my headers (I never was a great welder). It's not pretty, but they have held up to 10 years worth of abuse.

[Guest Anonymous]

My son and I installed an LT-1 in an '83 280ZX and we had to fabricate our own headers to clear the steering shaft and top of the rack. Hedman Headers of Cummings, GA sells a flange kit that will get you started. Like someone mentioned earlier, you need to buy some "J" bent tubes, also Hedman. My son and I made a set of headers in about two 8 hour days. Then we had them aluma coated at Millers Custom Powdercoating in Lilburn, GA Fortunately we had the use of a lift so we could get to the top or bottom of the motor with relative ease.

 

The folks at Hedman were great because at the time they did not make LT-1 headers at all so I brought them a factory steel exhaust gasket and for no extra charge they set up their trick numeric controlled plasma torch and cut us a pair of flange plates and welded 1" stubs for me to weld on to because they transition from rectangle to round. Very nice people and very knowledgable. Gave my son and I a tour of the plant. Awsum facility.

[grumpyvette]

--------------------------------------------------------------------------------

look here,more info

 

http://www.prestage.com/carmath/calc_headerlength.asp

http://victorylibrary.com/mopar/header-tech-c.htm

 

http://www.engr.colostate.edu/~allan/fluids/page7/PipeLength/pipe.html

 

http://www.feuling.com/randd/articles/art11.htm

[labrat]

Damn, using that formula, i need 72" headers!!! The collectors would be somewhere behind the transmission!

 

Bill

[danj]

Grumpy

 

I ordered 4 of the 5 books you recommended through Amazon/Borders. One of them wasn't in stock. They were about 25% cheaper on-line than in the local Border's store. On one of your links I noticed 2 more books by David Vizard called How To Build Horsepower Vol's 1 & 2. Are you familiar enough with these to recommend them or not? I have a long way to go to get up the learning curve so I'm interested in getting all the useful information I can while waiting patiently (anxiously) to get my 383 ZX converted.

 

DanH

[ZROSSA]

Dan,

I bought vol. 1 years ago and to be honest didnt get that much from it. It is not as well set out as some of the others that the grumpy fella mentioned. One of my favorites is "4 stroke performance tuning" by A. Graham Bell. Its not engine specific but bloody good reading. I still learn something every time I pick it up.

 

Cheers

 

Douglas

[danc]

DanH:

I have Heddman Tight tubes on my 83ZX with Rack& Pinion and the drivers side header has major modification. The last 2 tubes were removed from the flange and refabricated so the steering rod is running thru them with add-ons to the front tubes. The collector is now down around the oil filter boss. Looks more like a normal long-tube hedder. By the way, the Heddman folks re-ceramic coated the hedder for $50.

Dan