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The Hillclimb RX7 - a saga

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Old 07-30-12, 08:12 PM
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MA The Hillclimb RX7 - a saga

Figured I would post a build thread of for no other reason than to answer questions about the sport of hillclimb racing, which seems to be a bit of a niche sport.

I've been an avid autocrosser for seven years, last year winning my club championship in the SM class racing a 470 hp Acura Integra put together by Kinetic Motorworks in Hampstead, NH (great guys).


I've been a part of hillclimbing since 2009, first helping run the events and lately racing myself once I finally was in a position to do so (life gets in the way).

After racing my 1996 Miata (prepped for SCCA STS Solo racing), the missus decided i needed a full roll cage. In my first weekend racing I was 5 seconds off breakout time, which is the point where a full cage is required. Not bad for a 130k mile Miata that also serves as my daily driver.

Here's a vid: https://www.facebook.com/photo.php?v=3975152785257

Since the cage was a new requirement and this was my DD, a new car would be needed. I've always loved the sounds of rotary engines, especially since there's no sound limit at my favorite hillclimb, so I began digging around for an FC, which is a nice mix of affordable and good looking. FD's are too expensive so they were out of consideration.

I went with an N/A version over a turbo for simplicity, as I'd like to develop the chassis before adding power, but a turbo could be in the cards in the future.

I found this 1987 GXL with 113k on the clock and a 13B that had been (supposedly) rebuilt around 20k miles ago. The car looked nice and straight with zero body rust, with the only reason for its sale being a burnt out brake light switch or board. It won't pass inspection but I don't need functional brake lights.

I grabbed it for $2012 (it's a Grassroots motorsports thing) and dragged her home to begin the process of build a full-on hillclimber.

Here's how it stands right now:
Engine: K&N air filter, Racing Beat cat-back exhaust

Suspension: Koni yellow single adjustable shocks on stock springs.

Brakes: Corksport stainless steel brake lines, Brembo brake rotors, Hawk HPS brake pads

Wheels and Tires: Stock wheels with new Fuzion HRi 205/60/15 tires

Other: S5 taillights, Optima Red Top battery, recently replaced OEM radiator, silicone vacuum hoses.

OK that was lots of writing so here's some pictures.

First getting home and off the trailer:


Meeting the new room mate:


Time to start the tearing out:


This plate was last registered in 1989 by my aunt, so it's an homage (I'm a Vermonter born and raised and all the hillclimbs are in VT too)


Running out of stuff to take out. Only thing left is the dash and glass:


Wheels came in! 15x10 with a 5" back space:


I'll be running 23.5/10.0-15 American Racer modified tires in the super soft M28 compound. That's roughly a 275/35 tire. Yes I'll need flares.

Still deciding on spring rates... I'm thinking 400lb front 300lb rear. I'll end up buying a couple sets so I can test and tune.

That's where she stands right now. I need to get the glass removed and then the process cleaning out the sound deadening and caging begins. I'll document that process as well.

This post is already too long and there's no need to lay out plans. This car will be a constant work in progress and I don't plan on being competitive until next year. Hopefully I'll have my maiden voyage this September at the SCCNH Ascutney hilliclimb #2.

Big thanks to Death Metal Fabrication for all their help.
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Old 07-30-12, 10:22 PM
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Nice! Keep the updates coming.
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Old 08-01-12, 08:56 AM
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Warmup for my car. This is another FC that belongs to a fellow club member and hillclimber. Getting the a-pillar bars up and tight is a pain in the ***, especially since the owner didn't want us to cut up the dash (we still took a small notch out).
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Old 08-01-12, 11:39 AM
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And yes I'm aware there's a lot of layback in the main hoop. That was done before I got to the barn and was apparently a request from the 6'5" owner.
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Old 08-01-12, 02:29 PM
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What group are you doing hillclimbs with? Ive wanted to do any/all of the NEHA events however life always seems to keep me busy.

Cars been in and out of storage units and garages for 3 years now, still not done.

-Jacob
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Old 08-01-12, 02:49 PM
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NEHA all the way!

I'm the autocross director of the Sports Car Club of New Hampshire, which is a member of NEHA. You should come to an event even if it's just to check it out. Ascutney is by far my favorite.
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Old 08-03-12, 10:31 PM
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Well isnt it just a small world.

Ascutney does look good, ive met some of the DSG guys with there autox / hillclimb 240 a few years ago, they said the events were a blast as well.

My wife just had our babyboy a few nights ago, it might be a while still untill i get a car together

-Jacob
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Old 08-04-12, 01:57 PM
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Ah yes the MAXI 240. Bill Washburn is a damn genius. He was supposed to be down at NJMP this weekend hunting to set the record again but I guess the car has an electrical glitch.

DSP is sponsoring our fall Ascutney event, so I'm hoping the Pleasure Evo comes out. I have a ton of photos from past events at David Estey Photography | SmugMug
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Old 08-04-12, 02:03 PM
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Work on the car has been slow this week since I was helping my buddy get ready for the Okemo hillclimb. Today I've been working on the truck. We had a plastic bed line in it before we got the fifth wheel hitch, and it rubbed and caused rust in some areas. Cleaned up all the rust, degreased with Dawn and a pressure washer then prepped with brake cleaner and a scotch pad.

Here it is cleaned up:
[IMG][/IMG]

Here it is after one coat of Herculiner:


One more coat to go. I'm drinking a beer and playing GT5 while I wait for it to dry enough for the next coat.
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Old 08-22-12, 05:07 PM
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Progress has comprised mostly of ripping and tearing.

Just a few things left inside to remove:


Front is coming apart to get the A/C system all out:
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Old 08-22-12, 05:11 PM
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Got my GC setup in the mail too:

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Old 08-23-12, 12:50 AM
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Don't forget to get some good brake fluid to really take advantage of your new lines and pads. Looking forward to your build. Hill climbs are tons of fun! One of the most fun RX-7's I had was a GXL exactly like yours (same color and year). It had sticky 17" tires and springs but that was all that was needed to transform it into a very fun car to drive. Can't wait to see how yours turns out If you need any suspension pieces or bushings, check out my website www.j-auto.net. I'll be keeping an eye on this build and can't wait to see videos of your FC in action
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Old 08-23-12, 11:11 AM
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It has ATE Super Blue in it right now but since it was sitting I'll probably flush it and switch over to Motul RBF 600. I've been using this stuff in my Miata for a while now so it's more a question of what I have on hand than a performance advantage over anything else.

I'm checking out your site now, thanks for the heads up.
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Old 10-03-12, 03:50 PM
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Fell way behind on updates so I'm grabbing some from another thread I have:


Mounted up!


Red for race car. These are my extra calipers.


Interior is coming together. Seat is going in tonight as is the front suspension. I'll remove the rest of the sound deadening this winter when I cage it. Right now it's "Good Nuff". No, the gauge cluster won't be zip-tied in permanantly.


This is the side shot I sent to Kinetic Motorworks. They're going to vinyl the car for the hillclimb. They're supporting me with little stuff so I told them the car is their canvass this year. Eventually the car will be white with blue and red stripes ALA Racingbeat's racing FC RX7 from the 80's.
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Old 10-03-12, 03:51 PM
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Got the car buttoned up and good to go. These photos certainly show how much I'll have to flare things out this winter. I did run into a problem with the GC camber plates not being big enough for the strut shaft. No time to get the shaft machined down so I popped the stock top hats back in. This wasn't a test to see how fast the car would be after all, it's just a chance to put the drivetrain under pressure to see what I've got before I tear down again this winter.



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Old 10-03-12, 03:55 PM
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The real purpose of running in this event was to stress the drivetrain and see what I have. The answer: a damn fine running rotary. The car ran great all weekend with a slight miss at idle that I attribute to needing some fresh gas and plugs. Temps were great. No smoking and coolant stayed where it should be.

Handling was a little wonky due to my having to reuse the front top hats, which introduced some positive camber. The struts will need to be machined to fit into my camber plates. Still, the car proved very quick, taking fourth in class over a couple VERY experienced drivers in very well developed cars. My fastest of the day was a 2:34.XX.

The car is going back in the garage tonight and will be stripped even further to replace bushings, rebuild the LSD and do some seam welding before it goes to get caged. Also, the RacingBeat cat-back exhaust is for sale. The entire system will be replaced with something more in tune with track work. It sounds awesome, but is too quiet. People found it funny that the quietest car on the hill was a rotary.

MASSIVE thanks to Death Metal Fabrication and Kinetic Motorworks for their support.

Sidenote: I love my truck. 300 miles of towing, plus running the communications wire up the hill and taking it down on Sunday and I used half a tank of diesel.
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Old 10-03-12, 03:56 PM
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Old 10-03-12, 03:56 PM
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Tonight begins the process of tearing it all apart again. I'm not looking forward to sorting out the wiring harness.
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Old 10-03-12, 04:50 PM
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Sidenote: I did have a small off during the weekend, which bent one of the rear lateral linkages in the rear end. I had already planned to drop the rear subframe to clean it up and re-bush everything, but looking at the linkage design I'm considering moving to heim joints rather than the current ball-joint setup.

Anybody done that before? I would assume yes. I know groups like SuperNow make some, but they position the heim joint on a shear plane that I don't like. I would rather bolt on brackets to position the heim so it's vertical, wwhich should be much stronger given the movements it will undertake.

Last edited by DaveEstey; 10-03-12 at 04:54 PM. Reason: I can't spell
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Old 10-03-12, 08:09 PM
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theres really no reason to get rid of the stock lateral links, unless you lose toe adjustement at the trailing arm.

dont use poly/delrin bushings anywhere in the rear suspension!! fine for subframe/diff mounts. either stick with stock or get bearings for anyhting that moves.
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Old 10-04-12, 04:38 PM
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Originally Posted by Josh18_2k View Post
dont use poly/delrin bushings anywhere in the rear suspension!!
Why not?
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Old 10-04-12, 09:36 PM
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Trailing arms move in 3 axis. You either need OEM bushinsg (flex), or bearings (full rotational feedom). Delrin/poly is meant to slide about one axis and will bind.
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Old 10-06-12, 11:58 AM
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Originally Posted by DaveEstey View Post
Wheels came in! 15x10 with a 5" back space:
Which wheels are those? They look like Bassett? Do they clear the stock 5-lug front calipers without a spacer? And the GC coilovers?

My notes have the stock 16x7 as having a 5.675" backspacing and the coilovers open up some room so I was thinking a 15x10 with a 6" backspacing to help fender clearance... and most folks say they need a 0.25" spacer on the front to clear the calipers with the steel wheels...
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Old 10-07-12, 10:16 AM
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They're Aero wheels I think you could pull of a 6" backspace, you do need to run a spacer to clear the calipers though. The basket of the wheel hits just on the inside without one.
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Old 10-10-12, 11:13 PM
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AWR makes some toe links too, but they require you to drill out the tapered hole... and they have the same issue you don't like. I've never heard of one failing though, and a lot of people run them... (me included) it's also on the same shear plane the stock ball joint is...

Toe Link Kit - Rear - 1986-1992 RX-7 - AWR Racing Store

I also wouldn't mess with the mounting points too much. I measured the bump steer of the rear suspension with my awr links (other links may differ, but not much) and it was already amazing (less than .005" throughout the entire travel), so don't change any mounting points

awesome project though, I'll be following this thread.
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