25XP's X Prepared FC Rx7
 

I never got around to a "build thread" on my autox prepared Rx7, and it would have been a 21 year thread in the making. I have had my FC since 1990, and my attentions to it over the years have had life's destractions take me away from it from time to time. There were many small threads on TeamFC, but probably gone for good now, like my memory...
Thru the years, I never kept a good build sheet, or all my reciepts, and I was never one for technical geekness (no offence to those who are). I do tend to do my research at the time for a specific project, and find a way I can fit it into my skillset and budget. I have done all the work on my car except for the engine buildup and the Motec tuning. Learned it all from forums like this, and hands on, with a lot of just sitting there staring at the problem thrown in too.

So, I have started actually writting down my research in a build notebook, and I decided I would share my future projects along the way with you all.

For those who don't know, my car is an AutoX only car, that runs in X-Prepared. I have been autoxing for over 15 years, and I did okay on a regional level. Thus far the car is pretty well developed, but as aways, along the way there was not always time or money to do everything.

Recent projects:
Suspension:
I bought the AWR individual rear camber adjusters a year ago, and finally installed them. I have the center camber adjuster already, but I still had way too much negative camber. Even with 12" slick out back, they would light up way too easily. I am hoping to have zero negative camber when I align the car.
I also slotted the front strut towers to allow for more camber. The Hoosier 35A's don't need a lot of camber, but I was running into clearance issues and I was not able to get symetrical camber numbers. Free modification if needed.

Oil
As shown in the picture of Oil related goodies. When I installed my Mazdatrix oil pan baffle, I used only 1 gasket and gasket maker. It never seemed to seal perfectly, and I hate a leaky race car. So, 2 factory Mazda oil pan gaskets, Moroso stud kit, a FD factory oil pressure regulator, and Redline 50wt oil round out my oil projects. Oil related, but another to do project is redo the turbo dump line. Its AN fittings and SS line, and the short distance and angle was too sharp possilby and created an oil leak at the motor. More on that later.

I also decided to pony up some big bucks for an Ebay special short shifter. I couldn't pass it up, and I was dropping the tranny fluid and redoing the gasket anyway. Heck, I usually only shift once per run anyway, might as well be a short one. There is a great write up on this shifter already, so I will leave it out.

The bigger projects are the Jazz fuel cell, Bosch 044 pump, lines and Areomotive FPR install. I spent some time on the cell mount already (pics) and will update more when I run the lines and plumb everything.

I am happy that I can ditch the Nascar style rear spoiler that I was forced to run in BP, and now I can run a 2 plane wing. I am having the strut brackets designed at this time, and will post more on this as the parts come in.

The list continues, but thats it for now, on with the pics....
25XP

Dumb question: Why put the fuel cell up so high rather than buying/building one to hang low like the stock gas tank?

An overall description and pics would be good. You haven't mentioned a turbo, but I can't imagine you running in XP with a 044 and Motec without one.

From what I can see, your FC looks super clean.

Are you familiar with Steve O'belenes old S4 FC?

Not a dumb question at all, and I may rethink moving it below. The CG would be better below, so that would be a good reason to do so. When I initally thought about mounting the cell, I always envisioned above the rear deck.
Food for thought....
Thanks,
25XP

Which wheels and tire combos have you tried? Stock bodywork or something else? Thanks!

My turbo is a Garrett TE-460-1, .70 A/R Ptrim. HKS mainifold, Tial 38mm wastegate with a Turbonetics Godzilla blow off valve. Custom FMIC. 850/1000 injectors, Denso pump.
The car dyno'd just under 400hp in Denver, with a 50mm restrictor for the intake that I had to run in BP. The outside temp that day was 103, so maybe not the best pull. I removed the restrictor, and I am now in Norcal, so HP should be better, although I haven't dyno'd it yet.

Yes, I know Steve, I met him when I was at an event in CA, and I have spoke to him a few times on the phone when I was installing the Tri-Point wide body kit. Very nice guy, always happy to help.

Here are a few pics..
25XP

Subscribed! Clean looking car.

My wheels/tire combo are currently

Front 16x12 Real Racing wheels with 23x10.5x16 Hoosier 35A compound
Rears 16x12 Real Racing wheels with 25x12 Hoosier 35A coupound

They do make a 25A compound that tend to heat up faster, but wear quicker. I may try these in the future.

The real problem was I was simply getting too much negative camber in the rears with just the center camber adjuster. I had the camber adjuster maxed out with my ride height set for corner weighing. I should be seeing less negative camber with both the center rod, and the individual camber adjusters. Also a bit of body massaging to the tub where the suspension was most likely making contact during compression.

I know a lot of the FD autox cars run 18" wheels with Hoosier A6's and I have thought about that route when I buy new wheels. There seems to be some opinions on both sides as to what is better a DOT Hooiser or true slicks for prepared cars.

Also, to address the question, not stock body, TriPoint wide body kit.
Thanks,
25XP

Any idea how much wider the Tri-Point kit is compared to the AWR bodywork? I'm still struggling with a wheel/tire combo decision...

I don't have any exact specs on the difference, from the pics that I have seen, I would say the TriPoint is fairly bigger. What "fairly" is could probably be determined with a bit of reasearch. Tony at AWR may be able to answer questions as to what wheels were the AWR flares ment to fit.

From what it seems, the AWR kit is designed for the SCCA EP roadracing FC, so if you look up the rules to what the wides wheels allowed in that class are, I would suspect AWR made the flares to fit within those parameters.

The TriPoint was made for the SCCA AutoX FC in prepared rules back in the 90's. The "TriPoint" prepared car ran 16x12's. I have personally ran 16x12's with a "0" offset and they fit within the TriPoint wide body kit.

Hope it helps,
25XP

I've been trying to get Tony about this but he's strictly 15x7 23.5x9.5x15 EP slicks... he did refer me to another gentleman this morning, though, that I had a great chat with. He's got 15x10 with the Hoosier radial slicks, and more importantly, he's got 17x9.5 and 17x12 and says they fit inside the bodywork. He's going to get me backspacing numbers this evening. Thanks for your help! Appreciate it. And please keep us up to date with your car, it looks great!

FYI, You might consider contacting Joel ('frijolee' on this forum) from Ronin Speedworks since he has the Tri-point molds (improved) and sells the widebody kit now. He's very knowledgeable (as engineers can be) and can provide you with reliable data/info.

Those cheap fuel cells (I have one) will starve pretty easily. I have a 5 gallon one and it would starve with 2.5 gallons in it under cornering. Makes sense when you'll be generating between 1.25 and 1.5 G's. I had some internal baffling put in mine by a friend, but rewelding up that thin aluminum box was a nightmare, so I'd recommend trying to find a trapdoor type surge box that might fit through the filler opening.

I'm in San Jose and will be running in XP as well with my FD. Still got aways to go on being ready though. Should be out for early events next year.

-Andy

Well from what you say, that doesn't sound very good about starving the fuel cell.

Is your cell a 5 gallon Jazz cell? Does it have a sump? Foam? Where is your return line feeding into?

I was hoping to not have to do a swirl pot, but I may end up doing so if I run into fuel problems. I ordered all AN fittings and hardlines I think I will need for the installation of the cell, so a few hundreds bucks for another Bosch pump and swirl pot will be like a drop in the bucket!:crzyeye:

I hope we can meet up an event next season.
Thanks,
25XP

Remember this car from the other forum, Fantastic all around.

Any videos of the car competing ?

Good Stuff. Whenever I saw pics of your car I just always thought it was Steve O'Blenes' old car.

I have a Summit cell, but is basically same thing. Cheap foam on inside which doesn't do much other than shed little bits to clog your pre-pump filter, and a sump in the back that is great for drag racing. I ended up cutting of the top, putting in some walls around the sump with ball check valves, and running the return line over into that box.

Since welding was a total PITA the box I added didn't seal all that well, but it still works much better than as delivered. I'd be planning the external reservoir or finding some internal solution that fits through the filler hole. Problem with cutting these tanks is you need a pretty darn good Al welder to not have it warp like crazy when putting back together.

-Andy

^ you're switching to XP?? FFFFFFF (there goes my packwood NT tires :()

Thanks for the input and heads up on the cells issues. Would you recommend not running the foam these cells come with and save the pre filters potiential clogging?
Is there a better foam, or better not to run any at all?

I just got all my fittings filters and lines for the fuel system and will be mapping out the installation.

Thanks,
25XP

I ended up with no foam. While it helps with the slosh, it can't really stop the fuel from packing over to one side of the tank away from the sump. Part of my issues with the foam breaking off was due to putting the funnel to fill directly in the tank (no filler neck attachment). Every time you put the funnel or whatever in there and touch the foam, you can have little pieces come off. Over time enough can accumulate on the filter to be a problem.

Bottom line, these cheap cells were made for drag racing, not really road racing. A good cell with proper pickup will obviously cost alot more.

-Andy

Looking forward to reading more about the car. I love these threads. :)

FYI - Steve Kan is coming to town in mid Jan 2012 - see West section. So if interested in some tuning, get on it.

I am slowly talking myself into doing a swirl pot along with all the other fuel upgrades. I think I would regret not doing the fuel system the right way from the start. After Andy's replies about the cell, I figure I most likely will run into problems without it. I don't want to have to re-do the system or spend more time and money fixing a short cut.

So, time to read up on swirl pot set-ups.

I have seen some "homemade" swirl pots on this forum and others. Anyone with advice is welcome to chime in. If there are any members who are still fabbing them, please chime in too.


Update on what I have received thus far for the new system:
JAZZ cell with -8an fittings
1/2" aluminum hard line fuel lines for the feed side
10 micron -8an inlet/outlet fuel filter
Bosch 044 external pump
100 micron -8 inlet/outlet fuel filter
-8an to Y -6an splitter
Aeroquip SS -6an fuel line from Y to the fuel rails
-6an SS fuel line to Areomotive FPR
3/8" Aluminum fuel lines back to cell.
Assorted AN fittings to fit everything up.

I went with 1/2" hardl lines for the feed for ease as the fuel filters (Summit) had that size as well as the pump. It saved me a lot of downsizing reducers from the cell to the Y connector. All feed side fittings are -8an.

For a swirl pot, especially if one could be fabbed, I would like to stick with -8an inlet with -6an return to the cell.
I am thinking of running another Bosch 044 for the second fuel pump. Any issues with running that as the sump feeder pump?

Thoughts, ideas, suggestions, tips, tricks, rules, regulations or just good advice welcome.
Thanks,
25XP

I don't think you should need a second 044 pump; that thing is a monster. I moved mine from external to inside the fuel cell and added the in-cell surge tank... but that's for roadrace and you want a much smaller cell. In any case, I think two 044s would be complete overkill...

I need 2 pumps, one to feed the swirl pot and one to feed the rails.
I have read that some of the pre-made swirl pots need a low pressure pump to feed them.

Regardless, would need 2 pumps for a cell application.
Any suggestions on a swirl pot feed pump, if the Bosch is "too much"?
I have seen a lot of pics with dual Bosch 044, one for the swirl pot and one for rails.

Thanks,
25XP

Oh, I see how you're putting this together now, sorry, I hadn't thought it through correctly. Starting to feel like by the time you do a second pump and a swirl pot you'd be better off just getting a small fuel cell with a surge tank.