Turbo RX8
06-20-2006, 03:12 PM
#31
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Join Date: May 2004
Posts: 36
Originally Posted by wankelTII' post='822519' date='Jun 4 2006, 04:37 PM
The GReddy computer doesnt have anyway to control the fuel pumps in the rx8 so changing the fuel maps doesnt fix everything. At certain rpms and certain throttle position with the right load there may still be fuel starvation problems because fuel pumps are still running like they would with a stock tune. Fuel pressure fluctuates with stock set up. The Mazsport Interceptor allows you to fix this problem, so tunning is much more acurate. With the Interceptor, in my opinion, you still need an air temp sensor and a wideband o2 sensor, both specifically calibrated for the Interceptor. This will cost about $1000+ from Mazsport on top of the cost of the Interceptor. You may want to also do something to modify the fuel pick up because hard cornering with much less than half a tank may cause fuel starvation problems too.
If you want to control the fuel pump with the E-Manage, you can. But it is not necessary. The pump low speed is only engaged in verly low load. It is always at high speed when you are anywhere near boost so it isn't an issue.
With the Int-X, you will also want to calibrate for altitude, so a dedicated BARO sensor is a good idea.
The fuel starvation issue is mostly right-handers at low fuel levels. A secondary pump might be a good idea for that.
The turbo in the GReddy kit isnt big enough to hold more than 5 or 6 psi at redline, so no matter what you set the boost for, it will fall off up high. Mazsport is in the process of designing their own turbo kit i believe.
The turbo in the kit is good aout to 20 PSI on the Renesis. It is the WG actuator that causes the problems.
Rx8s have overheating problems so no matter what you do, the first upgrade should be either vented hood or radiator relocation, so hot air has a way to leave the engine bay. Aftermarket radiator will help too, but without a way for air to escape that wont be enough. Vented hoods seem to be the cheapest way to help with this problem, radiator relocation is most likely alittle better, but i think a vented hood usually does the trick.
Not all have "overheating problems". I think it needs to be addressed on a case-by-case basis.
Simply installing a larger rad has solved this in all the cases I'm aware of.
I live in the desert and regularly see air temps around 114°F. The surface taemp can easily top 160°F. I run full boost at high speeds for long distances under these circumstances without my coolant temps going over 230°F.
A vented hood simply moves the air outlet from the side to the top. No real benefit there, but it will screw up the airflow and cook things that wouldn't otherwise get cooked.
The renesis will hold up to boost if its tuned correctly.
Agreed. True for all motors. Bad tuning gives some motors a bad rap. I've seen far more bad tuning than good in my years and half of the time it was at the hands of "professional" tuners.
I would also get urethane engine mounts, or even solid mounts before you add much power to the cars, or even drive them hard in stock form. The stock liquid mounts suck really really bad and when they go bad your lower intake manifold will crack from hitting the subframe. Vibrations are almost non existant even with solid mounts, i have no idea why ford/mazda felt that liquid mounts were a good idea. Your whole drivetrain will last longer with harder mounts, soft mounts put alot of unnecessary stress on everything.
The OEM mounts can be filled with 80 durometer shore urethane for about $15. I did this and it makes the floping go away. There is some additional NVH at idle, but it is negligible.
If you want a reliable car that you can beat on like it was stock, then dont try to turbocharge an Rx8 without about $10,000 to throw down on all the stuff mentioned above. You may have to have engine mounts custom made, if you go solid you also may need engine mount brackets made because the stock ones are just cast aluminum and they will crack and break with time, but someone may already make something, i dont know. If you are going to have custom mounts made, then you should know the subframe is about 3 degrees from level and that 3 degrees faces away from the engine on either side. I believe this angle has to be compensated for in the top of the engine mounts or the engine mount brakets wont sit correctly. Anyway, I have gathered this info from working on the cars myself and talking to some of the people making parts for the rx8 so i am 99% sure its all good info.
The shear strength on the OEM aluminum mounts is almost as great as the control arms. It would take a significant impact to break them.
That said, building a box-tube around the connection tang on the OEM mount will cost $8 and take 30 minutes. "Problem" solved.
06-23-2006, 10:11 AM
#33
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Join Date: May 2002
Location: California
Posts: 22,465
Originally Posted by guitarjunkie28' post='825071' date='Jun 19 2006, 02:58 PM
yea, it has a few different staging options. primary hold, duty cut, has extra load bars, etc etc... it's got a lot of control to it.
the one thing it doesn't have that i wish it did is staging load vs. rpm. it's load dependant, but not rpm. if it had that, i could stage at say 10 psi @ 3500 rpm, and 4 psi @ 5k rpm... stuff like that.
i would love it if haltech did that, its the only thing really lacking vs the oem ecu's on the e11/e8 series, you can get it to do everything else
07-09-2006, 04:28 AM
#34
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Join Date: Jan 2002
Location: CT
Posts: 1,345
Originally Posted by j9fd3s' post='825649' date='Jun 23 2006, 11:11 AM
i would love it if haltech did that, its the only thing really lacking vs the oem ecu's on the e11/e8 series, you can get it to do everything else
why do you need that? it really becomes a problem with itbs, at which point you should use tps for load sensing.
07-09-2006, 01:28 PM
#35
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Join Date: May 2002
Location: California
Posts: 22,465
Originally Posted by kahren' post='827519' date='Jul 9 2006, 02:28 AM
why do you need that? it really becomes a problem with itbs, at which point you should use tps for load sensing.
its more of a want....
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