Duke's'72 Carbed KA project

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defdes
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Re: Duke's'72 Carbed KA project

Postby defdes » 15 Apr 2014 07:10

[quote="Sleepys-14" as the front bottoms every once in a while on compression bumps mid corner.[/quote]
What inserts are you using?

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Re: Duke's'72 Carbed KA project

Postby Sleepys-14 » 15 Apr 2014 07:21

defdes wrote:[quote="Sleepys-14" as the front bottoms every once in a while on compression bumps mid corner.

What inserts are you using?[/quote]

They are a 13" koni yellow with custom valving.
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 15 Apr 2014 10:00

Sleepys-14 wrote:Glad to hear the front bar mods worked the way you wanted. I am thinkin of stepping up to a 325# or a 350# like you have. I currently have 300 in the front and seems just a bit on the soft side, as the front bottoms every once in a while on compression bumps mid corner.


How much does the ecotec weigh? Compared to an L-series, the KA is a pretty big lump of iron right over the front wheels.
Duke Schimmer

'72 2-Door 510
"Simplify and add lightness."

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Re: Duke's'72 Carbed KA project

Postby Sleepys-14 » 15 Apr 2014 11:39

duke wrote:
Sleepys-14 wrote:Glad to hear the front bar mods worked the way you wanted. I am thinkin of stepping up to a 325# or a 350# like you have. I currently have 300 in the front and seems just a bit on the soft side, as the front bottoms every once in a while on compression bumps mid corner.


How much does the ecotec weigh? Compared to an L-series, the KA is a pretty big lump of iron right over the front wheels.


Ya know, I'm not sure how much it weighs... It is all aluminum, but its a pretty big block and head. I think they are around the 350# mark with the starter/alternator/header/intake. I thought the KA was around 400ish... but im not sure about that either.
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

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bertvorgon
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Re: Duke's'72 Carbed KA project

Postby bertvorgon » 15 Apr 2014 12:25

One thing, just as a point of reference, I have almost 3" of travel up front, with my combo. We found under extreme loading, then a bump, that that was kinda the travel we needed. I have a 1/4" bump rubber on the shock. Do not under estimate how much travel you may need, even with all the wonderful roll control.

I have only touched that bump rubber maybe twice, and that was only during very high speed, and a huge bump on our Canyon tours.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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Re: Duke's'72 Carbed KA project

Postby Sleepys-14 » 16 Apr 2014 06:22

I have about ~3.5" of travel in the front. I shouldn't say that I bottom out, the top of my tire rubs on the area above the tire under full compression. Duke, I know your car is pretty low... Do you rub very much on the top of the tire? On normal auto-x and road courses, I don't compress the suspension to that point but at our local track , we have a 3rd gear section that is down hill and right at the braking zone it has a nice smooth transition to up hill. But it fully compresses the suspension for about 1-2 secs. I notice the tire rub because of the smell and smoke from the front tires. Nothing crazy, but enough to get your attention. How much front and rear travel do you have on your car Duke?
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 16 Apr 2014 10:12

I have never checked travel. I know that both the front and rear do rub on the inner fender wells a little (not enough to hurt the tire, but enough to take the undercoating off). That being said the area the we autocross is not smooth at all! There are some very large bumps, breaks in the pavement, and even a section that with certain course setups a tiny bit of air time may be possible. So the suspension is really getting a workout.

I'll check travel in the front later tonight. The rear may be a little more difficult, but I'll see if I can get in there and see what I'm working with. To be honest, I know that I might be a little faster with the car a little higher, but I really like how the car is sitting now and I don't want to raise it, so I will just continue to make improvements to allow the car to work better at this height.
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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Re: Duke's'72 Carbed KA project

Postby duke » 16 Apr 2014 18:21

I just crawled under the car and took a look at the bump travel on the front. I have about 2" between the top of the tire and the inner fender (the lip around the strut tower has been flattened). The bump stop engages about .25" before this happens. The bump stop is very soft initially, so sure I contact the inner fender fairly often. However, I have never seen any evidence of this on the tire itself (grooves or otherwise) so it must not be to bad.

I would like to "tub" the front end sometime in the future to gain a little more travel, but with the front crossmember of my car being only 2.75" off the ground, I can't gain much more travel until I run into other issues.
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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Dave Patten
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Re: Duke's'72 Carbed KA project

Postby Dave Patten » 17 Apr 2014 13:24

Duke,
The tire to inner fender contact is why I could never understand why folks want extremely shortened struts. In most cases you never gain bump travel and you only lose droop. I'd say your particular tire/strut combination is pretty much perfect for the car's current configuration.

I trial fit a 280ZX strut, w/o a spring using T3 camber plates. With 205/50-15 tires, the tire would hit the inner fender on bump before the strut would bottom. Told me that I didn't need to shorten the 280ZX strut in my application. With shorter tires and/or a stock strut isolator the results would have been different.

On modified cars you can toss about all "rule of thumb" generalizations right out the window ... baby, bath water and all.
Dave Patten
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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 17 Apr 2014 14:14

I know what you mean Dave. I have Tokiko VW Rabbit inserts in shortened 280zx struts and I have to run pretty long bump stops because the strut housing is simply to short.

The other thing I don't really understand is how one could effectively run a tire that is any taller than a 205-50-15 for a performance oriented car. Talk about the tire hitting the inner fender!
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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bertvorgon
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Re: Duke's'72 Carbed KA project

Postby bertvorgon » 17 Apr 2014 15:03

23"..that's it!
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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duke
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Re: Duke's'72 Carbed KA project

Postby duke » 21 May 2014 09:47

I have wanted to build a new intake manifold for a while. The old one worked fine, but I wasn't really happy with how it looked, and I wanted to do something different with the water outlet. I had cut the flanges a few years back while I was still in college and they had just been sitting since then. I am glad that I waited to do this, as my welding has improved since then. My dad and I recently purchased a new to us welder (Miller Syncrowave 350LX) so I thought that this would be a great first "big" project for it. The main concept is pretty much the same as my old one, but the flanges are a little thinner (3/8" plate vs 1/2" plate to make welding a little easier) and the design of the water outlet is a little different. I have also included threaded bungs on the intake runners for the MAP sensor on my ignition and bungs on the water outlet for bleeding the cooling system and the temperature gauge. Overall, I am very happy with the end result. I didn't remember to take any pictures before I mounted it, so here are some of it bolted to the engine with all peripherals installed.

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I will soon be bolting on a set of 44mm Mikuni's to replace the 40's that I have been running in the past few years in hopes that they will give me a little more top end punch. In addition to this, I recently dropped in a fresh "rebuilt" (I put in new bearing and a new timing set and head gasket, every thing else looked perfect) engine to replace the old one that had been on it's last leg for a while (the last engine was a conglomerate of the good parts of two blown engines to make one good one). The new engine runs much stronger than the old one.
Duke Schimmer



'72 2-Door 510

"Simplify and add lightness."

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JordanTr
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Re: Duke's'72 Carbed KA project

Postby JordanTr » 21 May 2014 13:04

Very nice job. Those welds look top notch!

I'm sure your KA will enjoy the cooler intake charge from the isolated upper rad line. Are you still using the stock paper gasket for the intake manifold or did you go with a phenolic plastic based one ?
Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

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PoorMtnKid
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Re: Duke's'72 Carbed KA project

Postby PoorMtnKid » 21 May 2014 17:27

Nice welds, love the work you do!
looking for pass. side arm rest

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Re: Duke's'72 Carbed KA project

Postby Sleepys-14 » 21 May 2014 19:22

Fantastic fab work. Now put that thing on a dyno!
Beer... The cause of, and solution to, all of lives problems- Homer Simpson


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