Arca_ex

iTrader: (10)

Yeah I was just comparing transmission weight by itself. I'm guessing adding in a trans and diff mount and deleting the power plant frame will probably be a wash.

Even if the whole swap added weight I wouldn't really care. Since PT classing has a minimum weight, I can remove that weight from somewhere higher in the car and even though total weight wouldn't change, the CG would be lower which is beneficial.

I think even if I couldn't find somewhere else to take out weight if the trans swap was heavier, the benefits of a close ratio dog box would achieve lower lap times even with increased weight. Reliability is the main point anyways. Like I said before, all depends on whether or not the stock unit can handle it, which I doubt.

kbrewmr2

wouldn't you want to keep the PPF? I thought that was one of the things that made MX5s & RX8s alot better?

Arca_ex

iTrader: (10)

I don't see any advantages to it besides reduction of NVH by having the trans and diff isolated from the chassis and only connected to the subframes.

TeamRX8

iTrader: (25)

and non-PPF transmissions are not designed for that kind of loading either, but I think a few have been converted in the past, seems like maybe the Jerico racing trans as I recall

just saw that Par Engineering now has replacement dog & synchro gear sets for the S1 RX8 AZ6 6-spd trans case

not cheap, but a direct swap & bolt-in

Arca_ex

iTrader: (10)

That gearset looks nice and has good ratios but ouch... $6600 is pretty steep. I can almost get two completely built T5 dog boxes for that kind of money.

Need to start playing the lottery...

TeamRX8

iTrader: (25)

Except you need more than the box and then installing it all too, that said they'll need to confirm it will meet the capabilities of your particular application. Even the modded T5 has some failures below the stated power level.

dannobre

iTrader: (3)

If I win the lottery I will be getting a sequential

TeamRX8

iTrader: (25)

in my case it won't be an RX8

hocknscary87

Great build man. Between this and the 365 day rew swap thread it makes me wanna ditch the renesis turbo idea and go all out on an rew swap.

Arca_ex

iTrader: (10)

Decided that I can't wait for the dry sump pan anymore since it's taking longer than expected, I will be sourcing a stock oil pan and just build everything and put the dry sump stuff on later.



Also a friend of mine is going to Willow Springs next weekend and he made an offer to drop by any of the places he is a vendor for and hand deliver body pieces to save on shipping. That's a savings of around $150 bucks on top of the good deal he was already giving me so I ordered one of these.

It will give me more space for the v-mount. I don't expect fitment to be very good but it's cheap, and if I can clamp it to the car, it doesn't fall off, and it looks good from 50 feet away then I'll be fine with that.

FazdaRX_8

iTrader: (1)

with some time and attention durflex products can look good, if its warped just heat it up with a heat gun and use weights or something to hold it in place.

SiNfidelity

I have that bumper.

I did spend a few hrs cutting n filing etc but it does fit pretty good. My only complaint is the recess area for indicators. It's pretty bad there. It needs professional help haha. Saying that, if u can live without those indicators I think it would be easier to fill it in, smooth it off and just drill it for mounting bolt. I had to cut n shape it along the top edge above the indicator too, to form the the cars shape.

Warrior777

iTrader: (11)

Are you keeping your hood?

Arca_ex

iTrader: (10)

Thanks for the insight, that is kind of what I was expecting. I might just have the paint and body shop fit it for me when I get it sprayed.

Yep. It's getting even more cut up for the V-mount intercooler exhaust and I'm adding another row of louvers next to the existing ones that are running up the hood.

Arca_ex

iTrader: (10)

Well, I changed my mind on the turbo after getting several opinions of guys that have experience running REW's on track...
Going larger will bring down manifold pressures and EGT, I don't mind taking a small hit in spool and response in order to make life easier for the engine.




Not my picture but feel free to guess what it is.

FazdaRX_8

iTrader: (1)

watching your figure with 10 calories mmmm?

BorgWarner EFR 7163 Turbo?

BorgWarner EFR 6758 Turbo seems more reasonable

Arca_ex

iTrader: (10)

Nope those are baby turbos haha.

tmrx8

iTrader: (1)

EFR 8374?
What kind of differences are to be expected for EGT between this and a smaller turbo?

Arca_ex

iTrader: (10)

Nope.

It's an EFR 9180.

I'm expecting the EGT will be about 200 to 300 degrees F cooler. It will also help me with power under the curve using boost by RPM to achieve a completely flat horsepower curve, so at every RPM between 4500 and 8000 I can be making my maximum allowable horsepower in class.

Some people might be worried about spool and boost threshold on such a large turbo but thanks to the engineering that went into the EFR turbos, I should be able to make about 1bar by 4000RPM.

TeamRX8

iTrader: (25)

450 RWHP @ 4500 rpm???

unless you lowered the power limit from what I previously recll then I haven't seen anything close to that power/rpm point with said turbo on a 2-rotor

Arca_ex

iTrader: (10)

450 I won't quite be able to do at 4500RPM. That one will probably be 4750-5000 range where it can make that power.

The power levels for other classes will be able to make the max power figure from 4500 no problem.

Here's a small sheet I worked up for all the different configurations of the following factors, calculated with a minimum weight of 2800lbs.

DOT approved tire 275mm wide (e.g. Hoosier R6, Hoosier A6, Maxxis RC1, Nitto NT01 etc.)
Non-DOT 10.5" wide (Hoosier Slick, Yokohama A008, Michelin Slick)
Then Dog Engagement vs. Synchromesh is a different power modification factor as well.

These are absolute maximum numbers and I will likely stay about 15 to 20RWHP under any limit I choose in the event I have to do compliance testing on a Dyno.

Only thing is that I might not be able to make low enough HP for TT3. This depends on whether or not 7PSI springs in the wastegates will blow open in high boost operation. I won't know until it's on the dyno. If I have to switch to stiffer springs, I would likely make too much power even on wastegate pressure. I'm not really too concerned about this because TT3 in my NASA region is dog eat dog, and sometimes their times are the fastest overall times of the day... the top three drivers in that class would likely mop the floor with me haha.

I've put in bold which setups I would prefer to use for each class. You can choose whatever class you would like to participate in at the beginning of the event, so if it looks like the odds of winning tire contingency is better in a certain class, I can be flexible.


Unlimited
500+ Non-DOT w/ Dog Box

TT1
555 DOT
539 DOT w/ Dog Box
491 Non-DOT
475 Non-DOT w/ Dog Box

TT2
373 DOT
363 DOT w/ Dog Box
341 Non-DOT
333 Non-DOT w/ Dog Box

TT3
314 DOT
307 DOT w/ Dog Box
291 Non-DOT
285 Non-DOT w/ Dog Box

TeamRX8

iTrader: (25)

I haven't seen anything come close to that revised power/rpm point either. I don't see how you can get the boost that high at that low of an RPM with that particular turbo on a 13B, but maybe nobody has pushed it there yet. It seems to me that for that power/rpm range you're better off dropping down a size, especially for those lower classes. On E85 your EGT shouldn't be that big of a concern

Arca_ex

iTrader: (10)

Preferably I'd like to stay below 1700F for EGT's. Even on E85 it's tough.


Here's a local car that got tuned at the same shop that I'm going to. He's using a Borg Warner S366 which has nearly the same compressor and turbine wheel dimensions as the EFR 9180. The 9180 has better wheel design, wheel weight, flow capacity, spool, and it is ball bearing instead of journal bearing. Also I'll be using a 1.05a/r turbine housing, he had a 1.10a/r, both T4 divided.

He made 450WHP at about 5200RPM at 26 PSI.
It's going to be really close, we'll just have to see when it's done.

His setup:
E85
Street ported 13b-REW
2x ID1000 Primary
4x ID2000 Secondary
AEM Standalone
Borg Warner S366 with T4 1.10 Divided Turbine Housing
Dual 40mm external wastegate
3.5" downpipe and exhaust

Also note he was previously on a GT4088 with 1.06a/r housing, EGT's were mid 1800's, and now with the new setup and tune he's running just about 1700. A 35r size turbo would most likely be above 1850F if ran at the edge of what it can do.

TeamRX8

iTrader: (25)

the S366 flow map is similar to the EFR 8374, what I'm saying is that as good as the EFR 9180 response is for it's size you can still make the same power with even a whole lot more response

whole bunch of info on this with 13B on various forums, is your sponsor pushing you towards the EFR 9180? Seems kind of odd considering ...

Arca_ex

iTrader: (10)

Nope, definitely not being pushed towards the 9180 in any way. This is all just a product of my own research.

My application is kind of weird with the whole boost by RPM thing. A 500HP peak HP goal is just begging for the 8374, but if I want to be able to make big power down lower, it kind of makes things a little harder to decide.

The 8374 is definitely an awesome turbo and extremely responsive.

The things that kind of have me leaning towards the 9180 is lower exhaust manifold pressure, lower EGT, lower intake air temperature, lower intake manifold pressure, and more power under the curve for the flat HP map.

The upsides of the 8374 are definitely transient throttle response and lower boost threshold RPM.

Now going back to the power under the curve thing, the main class I will be competing in at NASA is TT1, so at NASA events, that is the priority. The bigger priority though is Global Time Attack, and there are no power caps there. I don't know how long I will run this car at NASA. I really want to do small bore race group with a Miata some day, and this car would just be for time attack events, reducing its use to maybe 3 events per year and just using NASA to do shakedown testing as needed.

Anyways. In that post they hit 426 ft-lbs of torque at 27PSI, the previous dyno graph shows that his torque curve is pretty much flat, so if I wanted to run a boost map with a 450WHP flat horsepower curve that spiked at 27PSI, I wouldn't reach 450WHP output until 5550RPM and above, where as the 9180 could potentially be making that number 550RPM sooner.

The other thing with running higher boost and having higher exhaust manifold pressure is that I have to run stiffer wastegate springs to prevent the gates from blowing open so who knows what the lowest output of each setup will be. Most likely a wash since I'll have to run stiffer springs with the 8374, so I can't really say if one setup would help with fitting into lower classes better than the other. You're definitely right that the 8374 will perform better at those lower power numbers but it's just not as high on the priority list for me.

I don't mind sacrificing a little bit of response in order to make that 450WHP plateau a little wider along with making life a little easier for the engine and having more headroom for Global Time Attack.


At least that's my reasoning... lol.


Or maybe I'm just a ricer and want to brag about having the biggest EFR while I'm hard parking at car shows.