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is anyone else interested in having some porting done?
i can't afford to do it for free because carbide costs me money...not to mention i spent like 9 hours on this one. but i can do it basically for the cost of the materials i use and maybe a bit on top of it for labor...but mostly just to see what kind of power it will make.
only concern is i don't have any idea how much power it would make, so there is some risk involved. i'd really love to see before and after dyno sheets.
didnt ito get like 50 hp when he ported his? and jim from racing beat says they only got 4 to 8 something not right.
I don't think Ito will say what he did to his car exactly. I would find it very difficult to see that the renesis gets anywhere close to 50 hp from just porting out the engine. Unless you are pushing more air into the engine (FI) this engine is already pretty well tuned. If somebody got 50 hp from just porting, I would rocket my ship to the nearest Mazda specialist and work on this as we speak. I remember Jim M. mentioned specifically that there was not nearly the amount of gain from porting the Renesis that there was from the previous generation rotaries. Could very well have to do with the design of the engines, but also that the other cars were FI'ed and able to use the extra intake, etc.
Actually when I talked to Jim, he never claimed any internal port work as of yet. He was more concerned with getting bolt on products finalized and then later on moving in to that arena. The person that claimed they have ported it was just a little part time guys. His story was never even consistent. The numbers Jim was talking about were just the bolt on gains so far. He's only seen 4-5 hp with headers, 3-4 with an intake, and a few across the exhaust. He has stated that he didn't think there were many gains to be had from porting since they were done so good from the factory but then he went on to say that the exhaust ports in the engine are terrible. This is a contradiction. We won't know for sure until we see one ported and someone actually takes pictures and verifies it after it runs.
Ito claims he hit 240 rwhp on his just off of bridgeporting the auxillary ports. His dyno looked strange to me though. There was a several horsepower peak where it jumped up to that number but fell down above and below it. I don't mean that power just improved when the auxillary ports opened and then climbed up to redline. There was a small peak in that rise and that is the number he quoted. That is worthless info. His power peak also came at about 7000 rpm or so when it should have come at 8500. Something is wrong with that. His motor is peaking where the 13B's should peak rather than where the Renesis should peak. The stock ecu also can't compensate and he claims that it hasn't been touched. He's done good work on rotaries in the past but he doesn't ever tell you anything useful and his dyno claims are misleading. It is also very rare that you ever see any pictures of his ports. There's nothing secretive about enlargening a port. You can stare at a picture all day but it doesn't mean that you can copy it.
Judging from the several rotaries I've ported so far, I don't see it taking me 9 hours to port. You can actually enlarge each port in about 15 minutes. The long part comes in cleaning them up and getting them smooth. It would still probably take a good 4-5 hours though. Don't even get into the time it takes to cut a bridge. I've done them and they suck to do.
Actually when I talked to Jim, he never claimed any internal port work as of yet. He was more concerned with getting bolt on products finalized and then later on moving in to that arena. The person that claimed they have ported it was just a little part time guys. His story was never even consistent. The numbers Jim was talking about were just the bolt on gains so far. He's only seen 4-5 hp with headers, 3-4 with an intake, and a few across the exhaust. He has stated that he didn't think there were many gains to be had from porting since they were done so good from the factory but then he went on to say that the exhaust ports in the engine are terrible. This is a contradiction. We won't know for sure until we see one ported and someone actually takes pictures and verifies it after it runs.
Ito claims he hit 240 rwhp on his just off of bridgeporting the auxillary ports. His dyno looked strange to me though. There was a several horsepower peak where it jumped up to that number but fell down above and below it. I don't mean that power just improved when the auxillary ports opened and then climbed up to redline. There was a small peak in that rise and that is the number he quoted. That is worthless info. His power peak also came at about 7000 rpm or so when it should have come at 8500. Something is wrong with that. His motor is peaking where the 13B's should peak rather than where the Renesis should peak. The stock ecu also can't compensate and he claims that it hasn't been touched. He's done good work on rotaries in the past but he doesn't ever tell you anything useful and his dyno claims are misleading. It is also very rare that you ever see any pictures of his ports. There's nothing secretive about enlargening a port. You can stare at a picture all day but it doesn't mean that you can copy it.
Judging from the several rotaries I've ported so far, I don't see it taking me 9 hours to port. You can actually enlarge each port in about 15 minutes. The long part comes in cleaning them up and getting them smooth. It would still probably take a good 4-5 hours though. Don't even get into the time it takes to cut a bridge. I've done them and they suck to do.
Well the dynos don't lie. Maybe the truth has been stretched, but he did hit that number. I'd like to see pictures as well and some greater explanation, I love learning about this kind of stuff even though I'm pretty new to it. I hope Racing Beat has some success with porting the engine when they get to that point, they're a group I'd trust to screw around with my engine. Thanks again for all of this info RG.
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Well the dynos don't lie. Maybe the truth has been stretched, but he did hit that number. I'd like to see pictures as well and some greater explanation, I love learning about this kind of stuff even though I'm pretty new to it. I hope Racing Beat has some success with porting the engine when they get to that point, they're a group I'd trust to screw around with my engine. Thanks again for all of this info RG.
I understand that dyno's done lie. He has also just hit a very similar hp number with his daughters 6 port RX-7 engine. Maybe a dyno doesn't lie, but how do you know the dyno you are looking at is for the engine you think it is? Something to think about when believing dyno claims.
I understand that dyno's done lie. He has also just hit a very similar hp number with his daughters 6 port RX-7 engine. Maybe a dyno doesn't lie, but how do you know the dyno you are looking at is for the engine you think it is? Something to think about when believing dyno claims.
Yea I guess so. I'll take your word since you'd have more knowledge on this subject, but I'd still like to see some more info from it. Time will tell.
__________________
Where do you go when it gets dark?
Is there room for me there?
How long will it take you to wake up?
Before you go will you wake me?
Dyno's don't lie, but they can be "tweaked". I'm not accusing any companies of doing so, just pointing out its possible.
1) Redyno the vehicle over and over again, until the perfect conditions are met.
2) Compare a just warmed up car, to a heat soaked one.
3) Turn the AC on for one run
4) Adjust the straps inbetween runs
5) Dyno the vehicle on different days, at different times, under different environmental conditions.
as previously stated, there's not a whole lot to be had from the intake. the engine can suck plenty of air in. now getting it out is another story...
Do you think that there is enough to do with the exhaust ports to open up 50+ whp?
__________________
Where do you go when it gets dark?
Is there room for me there?
How long will it take you to wake up?
Before you go will you wake me?
rotarygod what do you think the chances of porting only the the exhaust exit with the engine still on the car.i would remove the the manifold and start to grind away??
You can't. The exhaust exit that you can see is not what needs attention. It is the physical port openings in the combustion chamber that need the help. There's nothing you can do from the outside.
thanks rotarygod.that sucks because i cant get anyone who has experience to port my engine all the shops i call have never done an rx8 ,i called ito shop but he is to busy
if you want to take a small gamble, i'll port them.
i'll even do it for free--except the cost of the barbide burrs consumed ~$50.
all i want is before and after dyno charts.
it is a small gamble, but i do think it'll build more power throughout the rpm range. there's just no reason it shouldn't. i'm not sure what the actual hp gain would be, but if you see the before/after ports, you'll realise how much better they will flow.
if we do that, i don't want you to change anything on the car--no exhaust, intake, nothing except maybe just making sure the air/fuel ratio is about the same. i'd want to see what the porting alone gives power-wise, then we can see how much of a difference everything else makes.
alright.
first one is basically free--just reimburse for the materials... after that, i'll get some kind of a price together. there's a lot more work than there is with the rx7 motor....that's for sure.
Wow I usually just stick to reading the aftermarket section but I'm kinda glad I came over here. Junkie I live in Rancho it's about a half hour from you. If you're still game I'd love to work something out. I of course have no problem driving out there. My girlfriend lives half an hour away in the other direction so I'm used to the drive. The 15N is a bitch but we'll figure it out. Just lemme know and we'll PM.
Edit: Also my car is stock (unless you consider a green air filter to be a mod :p ) So we would see some interesting dyno figs.
Last edited by Snoochie; 11-18-2004 at 04:37 PM.
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