Not to turbo
10-10-2010, 02:23 AM
#1
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Not to turbo
I have been reading forums for some months now and I was very excited to turbo my 8, however, I have done a 180 turnaround. I will not be doing a turbo on this car. I love the idea, but I am uninterested in trying to spend all of my bank on something that will severely diminish the dependability and for the numbers I am shooting for would only put me on par with a 4.6L mustang, without the torque. This car is not a straight line car, it's beauty is in the turns. I am going ahead with suspension, clutch, flywheel, and some other little things, but I have bowed out of the big hp race. I think I would be doing it for the wrong reasons and I would enjoy the car about the same. I am an enthusiast and love the idea, but seriously I bought this car without the need to do anything to it, I loved it off the lot, sometimes one needs to step back and appreciate what they have I suppose. I am instead going to aim for keeping my 8 as pristine as I can, and perhaps do the unthinkable and get something with pistons if I have the urge to go fast, it is simply more dependable. Of course I will never give up my 8.
10-10-2010, 09:35 AM
#5
# 4.6L V-8: 315 hp and 325 lbs.-ft of torque
Mild turbo power will put your hp at 300 and torque at 250. You can easily get your torque up higher.
Keep in mind where the powerband is, just because your toque is lower doesn't mean you're slower. My TDI makes 260 torque at ~1600 rpm but the powerband is really only like 2000 rpm wide. The turbo RX8's band will be at least 5000 wide.
Mild turbo power will put your hp at 300 and torque at 250. You can easily get your torque up higher.
Keep in mind where the powerband is, just because your toque is lower doesn't mean you're slower. My TDI makes 260 torque at ~1600 rpm but the powerband is really only like 2000 rpm wide. The turbo RX8's band will be at least 5000 wide.
10-10-2010, 02:14 PM
#6
^ what he said.
Keep in mind that a 4.6 SOHC Mustang makes 325 ft-lbs at best...at the crank. That equals roughly 275 ft-lbs at the wheels. And yeah a decent turbo on a fairly conservative tune will be down about 30 ft-lbs from that...but weighing about 500 lbs less too. I know I've seen other turbo 8's with more than 250 ft-lbs. But its your car. I was very interested in a turbo for my car too, did my research, and decided it was simply out of my budget and not practical to do on my only vehicle. So now I'm looking into getting a Supermoto next year from KTM. 70 bhp in a 300 lb chassis with Brembo's, WP suspension, and a slipper clutch? Excuse me while I change my underwear please.
Keep in mind that a 4.6 SOHC Mustang makes 325 ft-lbs at best...at the crank. That equals roughly 275 ft-lbs at the wheels. And yeah a decent turbo on a fairly conservative tune will be down about 30 ft-lbs from that...but weighing about 500 lbs less too. I know I've seen other turbo 8's with more than 250 ft-lbs. But its your car. I was very interested in a turbo for my car too, did my research, and decided it was simply out of my budget and not practical to do on my only vehicle. So now I'm looking into getting a Supermoto next year from KTM. 70 bhp in a 300 lb chassis with Brembo's, WP suspension, and a slipper clutch? Excuse me while I change my underwear please.
10-11-2010, 08:20 AM
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It is not out of my budget, I just figure my money would be better spent on something else for now. This is my DD right now and I dont need to jeoperdize that. If I had another vehicle (besides my wife's miata) I be more inclined to turbo. I am actually a bit interested in the 3speed...I have much research to do before I undertake another project, I have too many irons in the fire right now and nothing happens until I am done with the 8. Which it shouldnt be long, as soon as I get home from this sandy vacation..
10-28-2010, 12:59 PM
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I was thinking the same thing. Turbo it up! But i think i am just going to get a bunch of extras ignition, wheels, exterior, exhaust like you are with the money i have saved. But it keeps pushing me in the back of my head to get the turbo.
10-31-2010, 03:59 AM
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About turbo or not
Well i am really new to this form i am going to get an RX-8 once i get home from my contract. I will share my experience. I have a friend that has rx-8 with a greaddy turbo kit the car was a blast with the turbo extremely fast. Now the bad thing fuel consumption was really bad almost 50 % more fuel. Second problem the waste gate on the turbo malfunction the engine was knocking the seals on the rotors got destroyed. All this happen in no time. The RX-8 motor is superior over the RX-7 it is more efficient it runs better it raves harder. But due to the lack of over lap of between intake and exhaust ports exhaust ports cooling with intake air cannot be achieved and if the engine is heavily turbocharged they will overheat due to the back pressure created from the turbocharger. So only mild turbo charging is possible how much is mild i don't know but i am sure you cannot run more then 10 psi without heaving problems with the exhaust ports unless you have some special turbo and special exhaust manifold. ( maybe this can be fixed with a divided turbine housing and equal length exhaust manifolds this is only my assumption i have to study the position of the port opening on the engine in order to be sure if someone has engine timing diagram intake compression power and exhaust in crack revolution please post ). On this engine in my opinion the only way is supercharger because it will not create back pressure on the exhaust ports and they will not overheat. Plus the supercharger output is steady fixed with the engine rpm so there is no chance for over-boosting and it should come with good bypass valve when engine is under low load and good blow of valve for safety when shifting. But again all this cannot be managed by the stock ecu because it is not designed to do it so now you need stand alone engine management and some how you have to connect all the engine sensors to it. On the end you will end up spending over 6000$ on engine alone plus maybe 1000 for installation you will get maybe around 50 % more power but you will compromise on engine live because is high compression 10 to 1 and then you have to upgrade clutch and transmission so it can handle the extra torque. In conclusion you spend over 10 000 to make something that you are hopping to work .
11-03-2010, 04:42 AM
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Nevermind, I am an idiot. OF COURSE I AM GOING TO TURBO IT! I just didnt want to spend the money, but seriously guys, I cannot get it out of my head. The turbo just keeps spooling in my head! soon....it will be spooling in my 8!
11-20-2010, 02:24 AM
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Why not to turbo
As far as this tread goes it was created for reasons why not to turbo the RX8 engine.
I have to say if somebody likes to put a turbo charger regardless of all the disadvantages associated with this setup on a engine made to be naturally aspirated please do so. But i just want to say if anybody wants to use force induction on RX8 my advice is to look at a super charger kit. This will cause less stress on the engine ( no more problems with back pressure on the exhaust ports created by the turbo) and better boost control because in order to raise the boost you need to change a pulley. I had a friend whit greddy turbo kit that had to rebuild the engine in 8 months after the installation because the turbo kit was not able to maintain the correct boost pressure. Engine knocking was happening and since the greddy kit comes with a pig back controller it didn't work as well as he was hopping for.
Good luck to all.
Alex
I have to say if somebody likes to put a turbo charger regardless of all the disadvantages associated with this setup on a engine made to be naturally aspirated please do so. But i just want to say if anybody wants to use force induction on RX8 my advice is to look at a super charger kit. This will cause less stress on the engine ( no more problems with back pressure on the exhaust ports created by the turbo) and better boost control because in order to raise the boost you need to change a pulley. I had a friend whit greddy turbo kit that had to rebuild the engine in 8 months after the installation because the turbo kit was not able to maintain the correct boost pressure. Engine knocking was happening and since the greddy kit comes with a pig back controller it didn't work as well as he was hopping for.
Good luck to all.
Alex
11-20-2010, 07:00 AM
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I went ahead with a kit I found (of all places) on the FS portion of the forum. Perfect it is not, cheap it was. Greddy it is. I just couldnt pass up the opportunity to have a fight with my wife (it was a bad one). I tried to tell her that we could just call it my christmas gift...wrong answer, she just got more pissed and decided that I have ruined christmas, I assured her I hadnt and that I still needed a clutch and flywheel...I should not have said that...
11-20-2010, 08:40 AM
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I went ahead with a kit I found (of all places) on the FS portion of the forum. Perfect it is not, cheap it was. Greddy it is. I just couldnt pass up the opportunity to have a fight with my wife (it was a bad one). I tried to tell her that we could just call it my christmas gift...wrong answer, she just got more pissed and decided that I have ruined christmas, I assured her I hadnt and that I still needed a clutch and flywheel...I should not have said that...
11-20-2010, 08:47 AM
#24
Fuel consumption doesn't increase considerably if you don't continuously push the car.
Why would he need an engine rebuild if the install is done right and the tuning is solid? Lol.
Why would he need an engine rebuild if the install is done right and the tuning is solid? Lol.
11-20-2010, 09:51 AM
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Who will spend money for turbo kit if is not going to push the car. Second this engine is not made for forced induction.Exhaust gases temperature goes up engine firing pressure will go up . There is a danger of scraping of the lube oil and micro seizures that will lead to premature seals failure. Overheating of the exhaust ports is a one more think to take in to account. The increased exhaust gas temperature and back pressure created by the turbo charger will reduce the speed of evacuating of the exhaust gas that can lead to engine damage ( overheating the ports).