Construction Zone
Don\
Welcome! Log In Register

Advanced

Tips for a RX7 Build

Posted by rallyRX7 
rallyRX7
Rob Garriock
Super Moderator
Location: Pitt Meadows, BC
Join Date: 01/26/2006
Age: Settling Down
Posts: 9

Rally Car:
2nd Gen N/A RX7



Tips for a RX7 Build
February 12, 2006 09:32PM
I am building my first car, a 2nd gen RX7 for production class and am looking for a little help.

I have the car mostly sorted out (rebuilt 13B, cage, seats, wiring … ) but now I need to dip into the pool of knowledge and find some info for my suspension and underbody protection.

I was planning to put on some 1 / 4 “ HDPE from around the firewall back and a 1/4” Al front skid. But the engine is up and out of the way so should I be able to go a little thinner? Layer Al and plastic? My concern is just protecting the rad and oil cooler. I also thought about making a pre-runner style bar to go from the cross member forward and then I can also use it to mount some lights on. Is making a carbon or Kevlar skid a feasible alternative? Will it cost more or less to make myself?

Is there a paycheck friendly suspension anyone knows of for the RX7? All I have really found is the dms, but $4500 is more than I want to spend.

If there is any other information people want to share, it would be appreciated.

Cheers,
Please Login or Register to post a reply
PAddy
Patrick McVeigh
Mod Moderator
Location: Toronto, ON
Join Date: 12/21/2005
Age: Settling Down
Posts: 358

Rally Car:
Student Loans



Re: Tips for a RX7 Build
February 12, 2006 10:31PM
Hey, you found the right place.

Others will chime in with better advice on what to do for some of your main points (I have a Crashlandingpad-brand suspension which I suspect is available for an RX7 for far less than a corner of DMS), but I ask you this:

Why are you thinking of running production?
Please Login or Register to post a reply
john vanlandingham
John Vanlandingham
Junior Moderator
Location: Ford Asylum, Sleezattle, WA
Join Date: 12/20/2005
Age: Ancient
Posts: 13,993

Rally Car:
Saab 96 V4



Re: Tips for a RX7 Build
February 13, 2006 11:02AM
PAddy Wrote:
-------------------------------------------------------
> Hey, you found the right place.
>
> Others will chime in with better advice on what to
> do for some of your main points (I have a
> Crashlandingpad-brand suspension which I suspect
> is available for an RX7 for far less than a corner
> of DMS), but I ask you this:
>
> Why are you thinking of running production?
>
> Patrick McVeigh
> Toronto, On
> Ford Sierra - Gp 5

Dit moi mon ami Paté,
ou acchatez vu votre Suspendaires JVABizoise?

Help the poor fellow in Colombie Britannique, you could give a link to www.jvab.f4.ca or the numero telephonique.
You even have nice photos, oui, non?






John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.
Please Login or Register to post a reply
john vanlandingham
John Vanlandingham
Junior Moderator
Location: Ford Asylum, Sleezattle, WA
Join Date: 12/20/2005
Age: Ancient
Posts: 13,993

Rally Car:
Saab 96 V4



Re: Tips for a RX7 Build
February 13, 2006 11:58AM
rallyRX7 Wrote:
-------------------------------------------------------
> I am building my first car, a 2nd gen RX7 for
> production class and am looking for a little help.
>
>
> I have the car mostly sorted out (rebuilt 13B,
> cage, seats, wiring … ) but now I need to dip into
> the pool of knowledge and find some info for my
> suspension and underbody protection.
>
> I was planning to put on some 1 / 4 “ HDPE from
> around the firewall back and a 1/4” Al front skid.
> But the engine is up and out of the way so
> should I be able to go a little thinner?

Hi Rob,
1/4" ali is sorta the standard, thinner wont be happy when your car lands on it.

Layer Al
> and plastic? My concern is just protecting the rad
> and oil cooler.
Well some people call it a "sump guard" And your rotary does have a sump.
Widen it out at the front and run a L bar from left to right that the sump guard leading edge rest on so it is reinforced and can't peel down when you nose in cause you might be surprised how close things can be when you have the fronts compressed fully and the back full extended.

As for the plastic stuff, its a typical good idea. some is good so acres is way better and why not 5/16ths? 11/32ths? Why not CNC mill out a block the sized of the car exactly conforming to the undersides shape?

A selective use of the plastic protecting leading edges of say rear suspension mounts and areas really subjected to gravel spray is one thing but the wholsale acres of platic is kinda silly.


I also thought about making a
> pre-runner style bar to go from the cross member
> forward and then I can also use it to mount some
> lights on. Is making a carbon or Kevlar skid a
> feasible alternative? Will it cost more or less to
> make myself?

Use aluminum, you can do what you need and those other things are expensive and do wear and die. Let the guys with unlimited budgets or stret bling boys buy Kevlar and Carbon fibre.
>
> Is there a paycheck friendly suspension anyone
> knows of for the RX7? All I have really found is
> the dms, but $4500 is more than I want to spend.

Yeah, have a look all round at www.jvab.f4.ca and you'll see locally made nice strong Bilstein upside down 40mm front/50mm rear shock stuff which costs in round figures about 1850-1900 depending on top mounts and who makes the "ears".
It is intended to be the best buy out there and it is.
It's fixed damping rate but we do 100% gravel in NorthAmerica so thats fine.
The rebuild costs are only ONE TENTH of the costs of rebuilding DMS.

You could call JVAB at 1 206 431 9696. I'm JVAB.
>
> If there is any other information people want to
> share, it would be appreciated.
OK what brakes to you have???
The nice 4 pot alloy calipers?
If you have 4 bolt wheels , switch to Gp2 and get the advantage of the looser structure in Gp2 and upgrade the brakes.

There is no rational reason to lock yourself into a class which dis-allows you the chance to junk-yard upgrade the car with "funn-er" bits.
P classes are for those who want to "hunt trophies", not for racers.
>
> Cheers,
>
> ______________
> Rob Garriock
> Pitt Meaodws, BC
> 87 N/A RX7
> 23






John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.
Please Login or Register to post a reply
rallyRX7
Rob Garriock
Super Moderator
Location: Pitt Meadows, BC
Join Date: 01/26/2006
Age: Settling Down
Posts: 9

Rally Car:
2nd Gen N/A RX7



Re: Tips for a RX7 Build
February 13, 2006 01:49PM
> The nice 4 pot alloy calipers?
> If you have 4 bolt wheels , switch to Gp2 and get
> the advantage of the looser structure in Gp2 and
> upgrade the brakes.
>
> There is no rational reason to lock yourself into
> a class which dis-allows you the chance to
> junk-yard upgrade the car with "funn-er" bits.
> P classes are for those who want to "hunt
> trophies", not for racers.


I figured it should be a good place to start, but it is more of my attempt of keeping all my spending on actually getting me out driving and not just on the snowballing effect of adding “funner bits” like a bridgeport. Because then I have to go and get a T2 trans and rear end, then a microtech to control it all. My cubical occupant budget doesn’t really allow me to spend oodles of money on my car. But it would allow me to put a better ratio in the back, the kia sportage 4.8 is said to be a nice fit.

Please Login or Register to post a reply
Morten
Morten
Mega Moderator
Location: Vancouver, BC
Join Date: 01/11/2006
Age: Possibly Wise
Posts: 366

Rally Car:
1974 Dodge Colt



Re: Tips for a RX7 Build
February 13, 2006 02:15PM
I think the point that JVL was trying to make is that you can upgrade with better than stock parts by going to the wreckers and buying used parts that you can adopt to your application. In doing so, upgrading the parts on your car as opposed to constantly having to replace using the inferior stock parts on your car.

I doubt the intial cost is more for a Gr. 2 car as opposed to a production car. You don't need to have the fastest Gr. 2 car in the field do you ? You're going out to have fun initially as opposed to winning trophy's, are you not ?

I've only done one Stage Rally and one Rally X. During the stage rally, I had plenty of things to think about than worrying about being the fastest car in the field.

On some of the stages... a Justy with a more experienced driver, posted better times than I did.

The point is, that you should build a strong, sturdy car and not try to squeeze yourself into Production because Production will cost more in the long run.

Far off base JVL ?
Please Login or Register to post a reply
john vanlandingham
John Vanlandingham
Junior Moderator
Location: Ford Asylum, Sleezattle, WA
Join Date: 12/20/2005
Age: Ancient
Posts: 13,993

Rally Car:
Saab 96 V4



Re: Tips for a RX7 Build
February 13, 2006 02:33PM
rallyRX7 Wrote:
-------------------------------------------------------
> > The nice 4 pot alloy calipers?
> > If you have 4 bolt wheels , switch to Gp2 and
> get
> > the advantage of the looser structure in Gp2
> and
> > upgrade the brakes.
> >
> > There is no rational reason to lock yourself
> into
> > a class which dis-allows you the chance to
> > junk-yard upgrade the car with "funn-er"
> bits.
> > P classes are for those who want to "hunt
> > trophies", not for racers.
>
>
> I figured it should be a good place to start, but
> it is more of my attempt of keeping all my
> spending on actually getting me out driving and
> not just on the snowballing effect of adding
> “funner bits” like a bridgeport. Because then I
> have to go and get a T2 trans and rear end, then a
> microtech to control it all. My cubical occupant
> budget doesn’t really allow me to spend oodles of
> money on my car. But it would allow me to put a
> better ratio in the back, the kia sportage 4.8 is
> said to be a nice fit.

Yeah I was thinking things like the ratio in the back which is the single biggest change and best investment you can do, then also the brakes. I get those 2nd gen calipers for $6.50 and the hubs/rotors I leave but they're cheaper than shit too.
You would have to be crazy to voluintarily choose a class which wouldn't allow you to slap on good brakes. And those second gen 4 piston things are good brakes (Lockheed made under licence by Sumitomo, pads interchange easily with the Toyota pickup IRON version on Mortens car.)

Don't worry about porting, get some sort of strong and quiet exhaust routed so it stays on the car, get gearing and brakes and good suspenders and GO.
>
>
>
> ______________
> Rob Garriock
> Pitt Meaodws, BC
> 87 N/A RX7
> 23






John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.
Please Login or Register to post a reply
rallyRX7
Rob Garriock
Super Moderator
Location: Pitt Meadows, BC
Join Date: 01/26/2006
Age: Settling Down
Posts: 9

Rally Car:
2nd Gen N/A RX7



Re: Tips for a RX7 Build
February 13, 2006 03:40PM
Morten Wrote:
-------------------------------------------------------

> You're going out to have fun initially as opposed
> to winning trophy's, are you not ?
>

But when I'm at the bar chatting up the ladies, I can tell them I finished 5th in calss and not 15th ( assuming only 5 cars in P class and 15 in grp2 )
Please Login or Register to post a reply
Morten
Morten
Mega Moderator
Location: Vancouver, BC
Join Date: 01/11/2006
Age: Possibly Wise
Posts: 366

Rally Car:
1974 Dodge Colt



Re: Tips for a RX7 Build
February 13, 2006 03:52PM
"But when I'm at the bar chatting up the ladies, I can tell them I finished 5th in calss", that's assuming that you don't toast your stock brakes and DNF !

Please Login or Register to post a reply
rallyRX7
Rob Garriock
Super Moderator
Location: Pitt Meadows, BC
Join Date: 01/26/2006
Age: Settling Down
Posts: 9

Rally Car:
2nd Gen N/A RX7



Re: Tips for a RX7 Build
February 16, 2006 11:25AM
Well by the sound of ti I will go group 2. So…

Has anyone ever lengthened a pinion? The nice 4.77 gear I can use has the right ring but is for the short housing, so it works on first gens, miatas and S2000’s but I would need to lengthen the pinion to get it working. Any one ever done this, anyone object to this? The car with a little work will only be about 185 hp. Getting 4.1 to 4.77 would be a nice improvement. The only better stock option is 4.33 but it is hard to find. A earlier trans from a first gen would change 1st form 3.475 to 3.674 , 2nd from 2.002 to 2.217 and 3rd form 1.366 to 1.432 and it fits in nicely too.
Please Login or Register to post a reply
john vanlandingham
John Vanlandingham
Junior Moderator
Location: Ford Asylum, Sleezattle, WA
Join Date: 12/20/2005
Age: Ancient
Posts: 13,993

Rally Car:
Saab 96 V4



Re: Tips for a RX7 Build
February 16, 2006 12:02PM
rallyRX7 Wrote:
-------------------------------------------------------
> Well by the sound of ti I will go group 2.

Smart move casue now you can swap in things.

So…
>
> Has anyone ever lengthened a pinion? The nice
> 4.77 gear I can use has the right ring but is for
> the short housing, so it works on first gens,
> miatas and S2000’s but I would need to lengthen
> the pinion to get it working. Any one ever done
> this, anyone object to this? The car with a
> little work will only be about 185 hp. Getting 4.1
> to 4.77 would be a nice improvement. The only
> better stock option is 4.33 but it is hard to
> find. A earlier trans from a first gen would
> change 1st form 3.475 to 3.674 , 2nd from 2.002 to
> 2.217 and 3rd form 1.366 to 1.432 and it fits in
> nicely too.

Forget all that shit. Toyota Supra MkIII has a short diff which is the next step up in terms of size and a couple of steps up in strength and WAIT!!!!!!
Ring and pinions NEW are about USD 175 and there are 4.88 and even 5.3 available
Go to www.JVAB.f4.ca and look around , there are photos of the one to get.
Fabbing it in can't be toooooo difficult, those wacky "moustasche bar" things can reasonably be ditched for something more compact maybe.
This diff is just the thing a normal Clubman wants, it IS the overcapacity that gives you long term reliability.
Bigger and much stronger than my usual fave for "live axle" rwd the DANA 30.

Think hard about this.
The diff comes stock in 3.9 or 4.3 (automatics and non-turbos).
>






John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.
Please Login or Register to post a reply
Pete
Pete Remner
Infallible Moderator
Location: Cleveland, Ohio
Join Date: 01/11/2006
Age: Settling Down
Posts: 1,927


Re: Tips for a RX7 Build
February 16, 2006 05:34PM
If you really really really wanted to use that 4.78 gearset, your best bet would be to acquire a Miata pumpkin and adapt it. A friend of mine did this for roadweenie driving in irregular circles use in an FC RX-7, rather than pay $500 or whatever stupid amount for gears that somebody else pre-hacked up and welded together.

So to recap, you'll need a custom driveshaft, gears, and diff center, and you'll still be stuck with the weenie gears... might as well go to that Supra diff thingie. Some other people who care about those cars have also adapted Ford 8.8" centers (found in '89-97? Thunderbirds, and IRS Mustangs if you want aluminum) and i think axles and such are already available if you have more money than fab skills.





Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.
Please Login or Register to post a reply
cablerhodes
Cable Rhodes
Junior Moderator
Location: Boise, ID
Join Date: 01/26/2006
Age: Midlife Crisis
Posts: 43

Rally Car:
Mazda RX-7 Turbo



Re: Tips for a RX7 Build
February 16, 2006 10:07PM
There are a bunch of mods you can do to a 2nd gen non-turbo without spending a bunch of time and $ on gears. If you don't have emissions testing or a way to get around it, take them off. You will get a ton more power. Put a header on at the same time, wire the secondary ports, take out the choke plates, buy good inexspensive suspension (i have Bilstein on my TII) like John's stuff or modify your own. If you have access, use TII drivetrain. It is much stronger and will last you well.

I have run my TII for two years now with only slight and very inexpensive mods. I do NOT have other than stock engine management, my drivetrain(except the engine) does NOT have less than 200K on it, and no DNF's.

Listen to these guys, as they all say the same thing. Spend your money on going racing and not on making the motor more powerful or the making the car prettier, cuz prettier doesn't matter after you roll or hit something inanimate!

If you need more RX-7 tips, feel free to contact me!



Cable Rhodes
Boise, Idaho
'87 Mazda RX-7 Turbo
Please Login or Register to post a reply
sagsert
Mustafa Samli
Godlike Moderator
Location: Arizona
Join Date: 01/10/2006
Age: Possibly Wise
Posts: 820

Rally Car:
Gaylant VR4



Re: Tips for a RX7 Build
February 17, 2006 12:13AM
Listen to Cable. He knows his RX7s.

He not only kicks AWD turbo cars asses regularly, he also knows how to fabricate proper windows out of corrugated cardboard.

Remember trees and burms don't yield so fuck pretty, make it reliable. Even better buy Cable's car so he can't kick our asses until he buys/builds something else.



Cheers
M.Samli
Phoenix AZ
Gaylant VR4
EVO III GSR (Stolen)


Rallies are no place for traitors
Please Login or Register to post a reply
Sorry, only registered users may post in this forum.

Click here to login