dmedz8

iTrader: (5)

why not?

WTBRotary!

iTrader: (6)

Lol? Unless you plan on competing hardcore taking all of that out is useless. I mean if your 8 isn't a DD then sure but if your not competing then I don't see the point as I give people (more than 1) rides all the time. But it's your car, you can do whatever you'd like.

dmedz8

iTrader: (5)

I don't give people rides often and its only one person if at all. Why did i do it? For fun, it was free, curious to see what it would look like. I also like how its louder inside without all the dampening material.

MazdaManiac

iTrader: (3)

Wow! $2k just to save 4 pounds in the rear?
Hard-core.

dmitrik4

iTrader: (5)

but street tire classes are cheaper!

from what i can tell, Team doesn't do half-*** prep.

TeamRX8

iTrader: (25)

First, I didn't pay $2k. It was a matter of being in the right place at the right time. TeamResourceful is just one more of my multiple personalities.

Second, I have the capacity of a full size battery (and 1000 cranking amps), which the Optima Blue I had in the trunk with mount weighed 48 lbs. If I wanted a small capacity battery it would be 4 lbs total with mount, but I had too many aggravations of them going low and having to be charged/jumped at inopportune times.

EricMeyer

Homeboy Team hits another one out of the park.

Sub 2,600 lbs is possible with a club racer cage and lots and lots of effort. Exactly like Team offers above, this is accomplished by often choosing to NOT use aftermarket parts.

Weight savings in a race car comes from a zillion little items, not a few that save several pounds. Many people don't get this. You need to do it a few times to fully understand where the weight is.

Here are some examples:

-Completely strip the chassis of everything and phosphate did her: 38 lb savings of seam sealer and sound deadening.

-Use minimum paint. Fancy paint is heavy and makes no h.p.

-Gut wiring harness: 30 lbs

-Use 1 3/4" .085 DOM tubing in only the required locations. Use .053 1.5" as much as you can. Note: Typical DOM tubing specs are .095 +/- .005 The 5 thou is worth a fair amount of weight. .053 1.5" is huge as well.

-Gut the hood, trunk, rear doors including the vertical heavy tubing inside them, gut the mirrors, pull bulbs and wiring for only the required lights of your series.

-Exhaust. Every part of the exhaust adds weight. Muffler weight can be heavy or light. Look into it. Dump the "pretty sound" attitude and go for weight savings. Less weight = more grip/faster car

-Cut out the horizontal seat mounts and use an aluminum one.

-Use aluminum every place you can.

-Don't make the mistake of running gigantic huge rims and tires that (a) are heavy, and (b) have more grip than the suspension and driver can handle.

-Invest in a fresh motor. A fresh motor can dramatically improve your power to weight ratio.

Many other things too detailed to offer.

vcoil

Hi,

Maybe you can be ispirated from

http://www.rx8france.com/forum/viewt...hp?f=8&t=18876

(on rotaryheaven.net I can't load the images eh Giorgio!!!)
Actually By removing and changing part with lighter ones I loosed 55.343kg, but I need to change other stuff like battery, remove floor things, airbags, but also to install a cage.

@Eric
Could you please MP me on how to 'wiring harness' because I'm a little afraid of it (EUDM rx8) and I can't afford a PCM swap to a Motec or other...
Another thing: have you some picture of your cage (I need to order one in Germany)...

Thanking you in advance

Davide

P.S. the front door trim is 6.39lbs, 12,8 both... I have a complete xls list of all the stuff I removed or just weighted but is not in english and it is in (g).

EricMeyer

Take everything out of your interior including the dash. Buy a Mazda wiring manual for your specific year. Start at the rear of the car and chase each wire to the relay on the drivers kick panel.

Highway8

iTrader: (11)

I plan to have a custom aluminum front crash bar built. The Main objective is to get it moved higher so I can open up the grill and allow more air flow across my intercooler and to the radiator. Side benefit for me the the weight reduction. I will have to add in a tow hook and mounts for my spliter struts.

I might do a rear bar too, but not excited about taking off the rear bumper.

Any suggestions on tube size and tickness? Honestly I dont want it too thick because it is designed to absorb impact so the vehicle chassis doesnt. I will probably add place some roll bar padding on the bar, again to absorb impact like the stock crash bar with foam is designed to do.

EricMeyer

Since you are asking about tubing size this tells me immediately that you are not aware of the rules and regs of legal roll cages. This is not something to mess around with. Why? Because 99% of the yahoos that think they can weld build a cage that gets DENIED when they get to tech inspection at a NASA, SCCA, BMW, POC, PBOC, etc event. Happens all the time. A guy with a brother in law that can weld says "Yup, i cin do that", and the project begins. I am being very serious about this subject. Why? Ever been upside down? Ever been backwards at 100+ headed to a tire wall? Ever looked at your drivers window and seen a car barreling down on you? You get my point I'm sure.

Cage fabrication should be done by someone who is not trying it for the first, second or third time. It is both an art and a talent in addition to incorporating a bunch of logic to make the final product user friendly.

What most people do is build a cage to the highest level sanctioning body they can and it is usually grandfathered into other sanctioning bodies. For example, a car build to an SCCA race spec is more often that not approved by NASA, BMW, POC, etc. Not always, but often.

How to build a car 101. A car is a car is a car is a car. DON'T look only at RX-8's to get ideas. Look at EVERYTHING. Your aluminum front bumper idea is great on paper but it will be both expensive and provide poor crash protection. Use mild steel. Get a bumper that can flow air for your IC before you build the car and work backwards. Same for the rear bumper. This is easy when you find someone who knows what they are doing.

Contact your local SCCA office and locate the people that do technical inspection of cars in your area. Every race car requires an "Annual" or annual inspection. The people that do these annuals will know who the better fabricators are. They will be glad to share these folks with you.

Last but not least. EVERYBODY who builds a car for the first times screws themself. More often than not an aggressive build schedule = more time and cost than someone budgets for. The best thing to do is have a super detailed game plan.

Hope that helps. Safety first always.

Eric

Highway8

iTrader: (11)

Eric thank you very much for the info, I do plan to build a race car one day, but that day is not today.

Right now, my car is a street car that I use for HPDE and time trials where cages are not required.

I have a professional Machinist, welder and fabricator that will do the work for me. He has done all kinds of race cars to meet SCCA and NASA specifications. I also have a friend that is a Nasa safety inspector and an RX8 owner. So when it comes time for me to do a race car, I have local resources avaialble that I will use to be sure I have a safe race car.

Back to my project at hand.

My understanding is that the front and rear crash bars are only designed to meet the 5 MPH crash test ratings, therefore I am not wanting to and should not build a strong crash bar like I would find on a race car. If I am wrong, please someone post up.

In regards to the intercooler, as with most kits for the rx8, cooling is allways a second thought when placing the intercooler.

I have the mazdaspeed bumper which has the large plastic piece at the top that covers the stock crash bar. My intercooler is placed behind that bar, so moving the crash bar up, will allow more air to my intercooler and to the radiator. It will also allow more airflow to a large oil cooler that will be placed between the intercooler and the radiator.

Ok, so now I have to explain more info about my car.

With the FMI installed, coolant temps on the track went up fast. We are talking 230-240 in 5 minutes. I had already done every little trick I could with a OEM fit radiator (BHR unit), sealed t of with foam, battery relocated to the trunk, vented out to try and help air pressure nad heat escape. Everything was great NA, but with a FMI and a 70% increase in power, it just wasnt cutting it. Additionaly my oil temps were coming up too, 240-250 with the stock dual setup.

So I took some advice from other FI members and installed a secondary radiator. I removed the stock dual oil cooler setup and installed the largest fluidyne oil cooler I could fit in the drivers size with 12AN fitting and a thermostat.

On the passenger side I went with a smaller fluidyne unit with 8AM fittings that I plumbed into the heater core system. Also running a thermostat. Immediately my coolant temp improved, I could drive the car hard for 20 minutes before every seeing 230, but my oil temps jumped to 260-265. Speaking to smarter people then myself, 265 oil is not a problem from a lubrication stand point, but it will bring the ECT up with it. So lowering the oil temps should lower my ECT. Additional it has been suggested that 265 might have contributed to the side seal failure. Motor is not apart yet, so the sideseal failure and more info will be discovered when the motor s cracked open.

Eric I have read everything I can find that you write and I have looked at all the pictures you post. From what I remember, you keep temps in the 210 range. I would be happy with 230 oil, 210 ECT.

So that brings us up to date, oh I forgot, my mazda reman motor craped out on me. Side seal just didnt like 300+ rwhp. A used 07 18K mile motor is sitting on a pallet ready for me to swap injectors and manifolds. My current motor will be sent to BHR for some work (another subject).

So my crash bar project is to improve airflow to the FMI and to a oil cooler I will place behind the FMI. FYI this new large intercooler is a fluidyne stacked unit. 28"X3"X4" 28X3 just happens to be the exact size of the black plastic piece I will be removing.

Rear bumper removal: I have read its not that hard, but then I see a hundred small steps in the DIY. I just need to do it one of these days. The front bumper looked daunting the first time, but now I have the thing off in 5 minutes with 2 small handtools. Honestly though, I am not as concerned about the rear crashbar weight savings as I am the front. Less weight is always good, but there is less to save, no added benefit of air flow and the rear is already lighter then the front.

I think that is about it. Questions, comments??

bse50

JDM and Australian crash bars are smaller (european ones should be smaller too)...
Ask Brettus to send you a couple of pics to get an idea of what i'm talking about.

Highway8

iTrader: (11)

That is what I heard.

I have seen the one on Kyle Mohan's RX8 drift car. He angled it down and used it has a mount for the radiator. I however will just need to angle it up a few degrees and incorperate a tow hook and mounts for my splitter struts.

TeamRX8

iTrader: (25)

Oil temp should never exceed 250 degF max, side seal is more likely an exhaust temp issue but proper oiling and oil temp impact it as well, switch to E85 and you will see improvements in every area


.

Highway8

iTrader: (11)

We are way off topic but...

I would love to switch, but its not going to happen right now.

BTW, side seal went out sometime between dataloging on a Tuesday and loading the car on the trailer two on a Thursday. Car ran great. Parked the car and it didnt want to restart, low vacuum, ran horible over 6K RPM.

The motor was a mazda reman that I never liked. Bad MPG, smoke, and 80PSI max compression.

MazdaManiac

iTrader: (3)

Fixed.

E85 is, per HP and per mile, more expensive, difficult to handle and, in many places impossible to source.
For instance, if I were to run on only E85, I could no longer do track events that were more than 200 miles from my home.

Having two calibrations - one for E85 and one for E10 - is a "solution", but you have to be certain that the tank is completely evacuated every time you switch on a boosted application.

Highway8

iTrader: (11)

Which is why I wont be going that way anytime soon.

When it becomes more popular, I might consider it.

WTBRotary!

iTrader: (6)

Sounds like my reman except I havent gotten a compression check on it yet...
I have 2-3K miles on it as well. Seems like I cant get past 16-17mpg with all my mods... Hell I should be seeing 23-24mpg with everything ive done to the damn car...

TeamRX8

iTrader: (25)

E85 is not just about teh powaaaa, there are numerous other benefits to using it on a Renesis especially for FI. Since you are in CA I didn't think it would be an issue, but for people who drive their car to the track where E85 isn't that popular it can be. If you are serious and trailering the car you should be getting it by the drum from a race source anyway for consistency reasons.



.

EricMeyer

Sounds like you have great resources for safety fabrication---congrats.

A couple of things. 1. you can't have enough cooling, 2. you can't have enough cooling and 3., get more cooling.

I'm not a big fan of placing one radiator in front of another. The turbo street crowd does this for packaging purposes but it is not as effective as one duct per radiator.

Congrats on relocating your batt, the larger oil coolers and watching your temps. I can share with you that the water and oil temps work symbiotically and lowering one helps lower the other. I suspect you've already removed your plastic inner front fender liners. I would guess that you've enclosed/taped up the stock black belly pan as well. If not, score some racers tape and go to town. Another thing I hope your doing is fashioning some air ducts for your oil coolers. Air likes to escape above, around and under the coolers. I think you could hit sub 220F with a proper design. We use a much, much larger dual pass radiator and can run that crazy thing on the 185 thermostat all day. This alllows us to tape up the front nose for better aero/less drag and still get solid air to cool the radiator.

Another thing you can do is create a intercooler specific duct and exit the expelled air UNDERNEATH your car. Foo foo to all the kiddies who think this is going to upset the airflow around your car and increase your negative downforce. They know nothing.

Is it possible that you have major big time Exhaust Gas Temps bcuz you are squeeking every last bit of power out of your engine? If so you are generating huge heat and you'll have more luck fattening your tune than cooling it. Something to think about.

Eric

MazdaManiac

iTrader: (3)

Like?

Charge cooling? That is for power. Lower combustion temps? Also power.
Lower EGT? Same.
The old chestnut about lower engine temps because of lower combustion temps turn out to only be true for 2 or 3 minutes at a time, after which the laws governing loss of energy do their magic.

The thing I like about it the most is what it does to your fuel injectors and pump.

Highway8

iTrader: (11)

The FMI kind of forced me to package them in there.


I have not removed the fender liners. What is the advantage of doing that? Do you remove the plastic behind the oil coolers too? I have significantly enlarged the vents out the back but they are still in place.

I have racers tape and I have sealed up the stock plastic undertray but I need to work on the ducting to the oil cooler in the drivers side.

Are you saying I could make an exit duct for the intercooler out the bottom of the plastic undertray? I would think the radiator could use that air.

My tune was a little lean, I am getting some bigger injectors and will be sure to have the tune fattened up.

EricMeyer

we've found there is more temp reduction in tuning than about anything else. That extra 3 or 4 peak hp is not worth the additional egt increase.

Additionally, there are a few smart people on this forum that use and know about higher oil pressure regulators and modifying the oil passages so that flow increases. These are great things to do when you are rebuilding a motor. Same for a new oil pump (cheap).

Let us know how things turn out!

TeamRX8

iTrader: (25)

Lol, your counter to chestnuts is to toss peanuts ...