FD, Fact vs Fiction 101 (very long)
06-15-03, 11:51 PM
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FD, Fact vs Fiction 101 (very long)
Ok, My experiences so dont shoot the messenger. There is so much good information and yet so much crap on this forum I thought I'd post what I have found.
3 mod rule: Fiction. Well on the surface its fiction until you see the reasoning behind it. Airflow mods on an rx7 tend to make it boost over the stock 10 PSI. this is where your problem is. If you can keep the boost to 10 PSI, you can keep a midpipe if you want. Well you get the idea. In otherwords if you have a way to control boost the 3 mod rule doesn't apply.
Mid Pipe makes you have terrible low end power: Fiction. Sorry, I found little loss of low end power when I went to a midpipe. Infact, even with a ported engine now, I have a slight loss, but its not what you read about on this forum.
If you have a midpipe you will get boost creep without a ported waste gate: Fiction. Well for me it was anyway. I never got boost creep even with a straight through catback (fully open exhaust) going down the 1/4 mile strip. My wastegate was stock. This is not to say you cant get it. Im simply saying it did not happen my case.
Midpipes are so loud. Sort of fact and sort of fiction. It all depends on your catback. I have a basic HKS and I have a straight through exhaust. with the HKS my car is as quiet as with a cat (except at 6+ RPM). With the TSUDO Fireball its loud at idle and is crazy even at cruise.
A midpipe will give you more HP than a High flow cat. Fact and Fiction. I had a modified stock air box (ram air from under the car) and a highflow cat, I had the stock air box replaced with an aftermarket (rx7fasion, aka M2) and got a midpipe. My trap speed dropped by about 3-4 MPH. I could not understand. When I made a ram air for my rx7fasion box, my trap speed was 5 MPH faster than with the exact mods on my highflow cat. The moral to the story? The intake is more critical to your car for making power than a mid-pipe. The solution? Ram cold air from under the car to make the most of the midpipe. But yes, the most bang for the buck is a midpipe. I dynoed with a HFC and then with a MP and gained 30 rwhp from the mp (with my ram air).
power FC doesnt control boost good: FICTION.
You cant paint the manifold, rotaries run too hot it will burn off. FICTION.
I painted mine like 4 months ago with some high temp paint from pep boys, doesn't come off.
you have to powder coat wheels, paint will not work: FICTION. painted my wheels about 7 months ago, not a chip.
RX-7's are unreliable. FICTION. Now before I get flamed...There is a difference between being unreliable and requiring maintenace. For example, Joe just bought an rx7 that was not maintained, it has 110K and the original vaccum hoses that are all cracked or were put back together wrong. he thinks his car is unreliable. Fact is, if you maintain things like the vaccum hoses the car will be very reliable. Yes, the engine will last between 50K-120K, but thats engine longetivity, not reliability IMHO. A different issue.
RX-7's make terrible Daily Drivers. FICTION. But This depends on what you want it for. An Rx-7 makes as good of a daily driver as a C5 would. If you can deal with bad gas mileage and no luggage or storage space, its great.
Anyone who posts a thread like "I need a car that will never have any problems and is very cheap to maintain" Should avoid an FD. FACT
The -7- CAN'T lose!!!: FACT.
ZeroBanger has way too much time on his hands: FACT.
3 mod rule: Fiction. Well on the surface its fiction until you see the reasoning behind it. Airflow mods on an rx7 tend to make it boost over the stock 10 PSI. this is where your problem is. If you can keep the boost to 10 PSI, you can keep a midpipe if you want. Well you get the idea. In otherwords if you have a way to control boost the 3 mod rule doesn't apply.
Mid Pipe makes you have terrible low end power: Fiction. Sorry, I found little loss of low end power when I went to a midpipe. Infact, even with a ported engine now, I have a slight loss, but its not what you read about on this forum.
If you have a midpipe you will get boost creep without a ported waste gate: Fiction. Well for me it was anyway. I never got boost creep even with a straight through catback (fully open exhaust) going down the 1/4 mile strip. My wastegate was stock. This is not to say you cant get it. Im simply saying it did not happen my case.
Midpipes are so loud. Sort of fact and sort of fiction. It all depends on your catback. I have a basic HKS and I have a straight through exhaust. with the HKS my car is as quiet as with a cat (except at 6+ RPM). With the TSUDO Fireball its loud at idle and is crazy even at cruise.
A midpipe will give you more HP than a High flow cat. Fact and Fiction. I had a modified stock air box (ram air from under the car) and a highflow cat, I had the stock air box replaced with an aftermarket (rx7fasion, aka M2) and got a midpipe. My trap speed dropped by about 3-4 MPH. I could not understand. When I made a ram air for my rx7fasion box, my trap speed was 5 MPH faster than with the exact mods on my highflow cat. The moral to the story? The intake is more critical to your car for making power than a mid-pipe. The solution? Ram cold air from under the car to make the most of the midpipe. But yes, the most bang for the buck is a midpipe. I dynoed with a HFC and then with a MP and gained 30 rwhp from the mp (with my ram air).
power FC doesnt control boost good: FICTION.
You cant paint the manifold, rotaries run too hot it will burn off. FICTION.
I painted mine like 4 months ago with some high temp paint from pep boys, doesn't come off.
you have to powder coat wheels, paint will not work: FICTION. painted my wheels about 7 months ago, not a chip.
RX-7's are unreliable. FICTION. Now before I get flamed...There is a difference between being unreliable and requiring maintenace. For example, Joe just bought an rx7 that was not maintained, it has 110K and the original vaccum hoses that are all cracked or were put back together wrong. he thinks his car is unreliable. Fact is, if you maintain things like the vaccum hoses the car will be very reliable. Yes, the engine will last between 50K-120K, but thats engine longetivity, not reliability IMHO. A different issue.
RX-7's make terrible Daily Drivers. FICTION. But This depends on what you want it for. An Rx-7 makes as good of a daily driver as a C5 would. If you can deal with bad gas mileage and no luggage or storage space, its great.
Anyone who posts a thread like "I need a car that will never have any problems and is very cheap to maintain" Should avoid an FD. FACT
The -7- CAN'T lose!!!: FACT.
ZeroBanger has way too much time on his hands: FACT.
Last edited by ZeroBanger; 06-15-03 at 11:56 PM.
06-16-03, 12:06 AM
#2
RX-7's make terrible Daily Drivers. FICTION
ZeroBanger has way too much time on his hands: FACT
Last edited by Recipe7; 06-16-03 at 12:11 AM.
06-16-03, 12:16 AM
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Originally posted by herblenny
Interesting write up.. I agree with most.. But with midpipe, I do get boost creep.. Even with PFC, and AVC-R... but not too bad... I set mine at .85bar and get .92.
Interesting write up.. I agree with most.. But with midpipe, I do get boost creep.. Even with PFC, and AVC-R... but not too bad... I set mine at .85bar and get .92.
06-16-03, 12:26 AM
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The FD seems to be inconsistent in terms of how it reacts to modification: FACT.
Someone may read your post, decide to do all the stuff that lots of people complain about (that apparently didn't happen to you) and come up with exactly the opposite list. I think the bottom line is that for any given car, don't assume that what happened to everyone else won't happen to you. I'm not sure why that is so apparent with this car, but it is. Also, some of your listed experiences are probably interrelated, e.g. the boost creep issues and the fact that the PFC controls your boost well. If your car had issues with creep upon addition of a midpipe, maybe the PFC wouldn't do such a great job of controlling it either.
It would be interesting to have two identically modified cars, one of which is like yours and the other with more of the issues. When working, would the car with issues be faster? I'm taking a guess that it would (no offense! :-) because it seems like perhaps those cars are a bit more close to the edge out of the box. I have no data to support it, but it seems logical.
jds
Someone may read your post, decide to do all the stuff that lots of people complain about (that apparently didn't happen to you) and come up with exactly the opposite list. I think the bottom line is that for any given car, don't assume that what happened to everyone else won't happen to you. I'm not sure why that is so apparent with this car, but it is. Also, some of your listed experiences are probably interrelated, e.g. the boost creep issues and the fact that the PFC controls your boost well. If your car had issues with creep upon addition of a midpipe, maybe the PFC wouldn't do such a great job of controlling it either.
It would be interesting to have two identically modified cars, one of which is like yours and the other with more of the issues. When working, would the car with issues be faster? I'm taking a guess that it would (no offense! :-) because it seems like perhaps those cars are a bit more close to the edge out of the box. I have no data to support it, but it seems logical.
jds
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