They basically said the rx8 was not good to go FI due to the height of the apex seals. Thoughts?

 

My advice is that any shop who would say that probably isn't competent enough to know what they are doing when it comes to rotaries and should be completely avoided. Go somewhere reputable. Talk to Mazsport for some real world contradiction to that statement.

 

my tuner (who is considered a top rotary tuner here in nz) said something similar .
Words to the effect " the renesis is not as strong as the REW13B due to the seal size " .
He has already seen a few seal failures but I do wonder if this is in fact the case as many here say the opposite.

 

Ask how many boosted 13B failures he's seen over the years.

 

13 PSIG is a safe boost for the seals - its the tuning that will kill them

 

Nemesis8 is that fact or just your guess, because you know that I have seen the 13B-rew
at 26 psi and is still running strong . If there is any truth to this (seal height) then that would be a reason for me to swap to a 13B instead of trying to boost the Renesis any more then that...

 

what tuner shop, post their name

 

Back when I first considered my nitrous project I heard the same type of concern over the seals from a supposed " rotary expert". Not only do I think that the shop I visited are all idiots for having spoken in ignorance, I have heard several stories from close friends and others in our local area regarding the shop I am referring to and their lack of professionalism and customer care after the job. It is for these reasons that I have pondered opening my own shop. I am far from being a genius but I know my limits and am honest about them. Potential customers seem to like that more than anything else.

 

That's what I hear rom most of the "tuner Shops" as well...."the engine can't handle much boost...it has weak seals and the compression is too high" "pull it and install a 13B"

They don't know much about this engine...and are afraid to blow them up...so they stick to what they have figured out. The formula for the 13B is almost bullet proof...and that is what they do.

Thankfully there are a few shops like Mazport...and guys like Scott...and others that are willing to try at least to see what the potential of the engine is.

From my perspective.......Like Charles...the thing doesn't seem that fragile???

 

^^ I think you hit the nail on the head. The 13B has been around in one form or another since the mid 80's. It's posted up in rx7club.com like a reciepe of power- just add the parts and you're garranteed 500-rwhp with good reliabitly.
The Renesis has been around since 2003-04, and people are affraid to explore the limits of this new, uncorked engine. Obviouisly, a tuner shop that wants to keep it's reputation can't go around promising people they'll boost their RX-8 only to blow it up- they'll go outta business. Shops need to do some R&D and take it easy, break it and learn method- just not on customers cars!
I remember when the 3rd gen RX-7 came out, people thought the power cap was around 350-hp, then every year it progressed. Until now, where it's common to see 500-rwhp FD's, and dedicated dyno queens and track ***** have over 700-rwhp on race fuel- i.e. non streetable.
Just give them Renesis some time.


Dave

 

Team,

I do not want to post their name. I'd rather invite the person I spoke with to the board to give him an opportunity to discuss his background and his positon on the renesis.

From what little I know of them, they have a solid reputation in the area but it is not a known rotary shop. They do lots of work on them and they have a resident rotary "expert". But they are definitely known for working on Supra's, Subaru's and Nissan's.

FWIW, I contacted them about getting my car corner balanced and a baseline dyno. My baseline dyno question lead to the conversation of what am I ultimately looking for which he then said I would not be able to get a reliable amount of increased HP with the renesis.

 

My point wasn't that shops should stick their necks out, just that they should be honest about that which they don't know and stop acting like they have solid proof as to what the Renesis can/cannot handle. The irony is that these "pros" should do a little research, themselves, and learn from this forum that which we all have discovered and discussed. pd, what is it that you are trying to do?

 

I've seen 13B's blow up at 250 hp before due to bad tuning. I've seen stock block 13B's top 600 hp with good tuning. The fact of the matter is that everything in the Renesis is stronger than the 13B. Even the apex seals are stronger. I know they aren't as thick overall but here's what that doesn't matter. The stock 13B seals are 3 pieces. There is a small triangular corner piece and then the other 2 pieces stack on top of each other. The total thcikness of the Renesis apex seals is no less than either of these 13B pieces. The apex seals on the Renesis are stronger than any one piece of the 13B apex seals. Consider also that the Renesis apex seals do not go over an exhaust port which fails to support the middle of them at this moment. Now tell me again how a Renesis apex seal is any worse than those and remember, the 13B seals in the hands of the right tuners (the big rotary tuning secret!) have gone over 600 rwhp.

The Renesis is no different than any other rotary engine when it comes to what it can do. Yes the high compression ratio is ultimately a limitation (per octane fuel used when compared against a low compression engine) but this limit is still over 400 hp on a street engine. That's plenty.

I fully expect the shop to use the standard "you can use different sronger apex seals in a 13B" argument but this is true of the Renesis too. If a shop isn't capable of giving you a realistic answer and at least some good supporting info to back it up (please remember that more 13B's have been blown up due to bad tuning than there have been Renesis engines ever built!), they should at least be honest and tell you so rather than trying to get you to spend tons of money with them to get a swap done that is unneccessary. If you are building a true race only car, that's a different story.

 

It'd make more sense if they tell you the weakest link is the side seals in an all side port rotary...
________
Sharonhotxxx

 

 

I know we have alot of Rotary experts here, and I trust what they are saying, But do we know of anyone in the engineering dept at Mazda Who can honestly answer these questions we have as to, If the Height of of these seals will give us problems when trying to Boost and or reliability problems when really pushing the Renesis over the 13B..

 

pdxhak there are only 2 shops in this area you should even consider having work on the car. thats corksport and pineapple racing. i havent asked corksports opinion but i was at pineapple just the other day talking with Rob and Blake. they have doen a few tcharger install- greddy- and were not impressed at all obviously. get one of the Mazsport kits and bring that to them- id like to be there for the install

 

i don't see what the real big problem with the statement is... i don't see people boosting 20-30psi and making rediculous amounts of power like in the FD -shrug-

... thats not saying the renesis won't handle boost or make respectable power though, its just not as good for forced induction as a lower compression 13b

 

Don't you get it? Renny is just a better and structurally stronger engine.
Just give it another 3-5 years, and you'll see.
The problem here is that most of them are still under warranty. People don't wanna just go in and start blowing up new cars. Once the RX-8 starts hitting junkyards and exchange second, third and fourth hands, so you can get it for cheap... Just wait and see.

 

with 10:1 rotors, i just dont see the renny boosting much past 20#. im not saying that it wont make power, just that it will make a different kind of power. id like to see a renny with 9:1 rotors though. for NA, there is almost no power difference from 9:1-11:1 so it would be interesting to see just how far we could push things.

IMO for BIG power, the side ports have to be addressed as well. although port surface has been increased, those 90 degree bends are too restrictive.

 

A high compression ratio engine isn't going to be boosted as high as a lower compression engine. This aplies to any engine. Put 10.0:1 compression rotors in a 13B and see how much more likely you are to detonate. That engine can't do it either so it's ludicrous to blame the Renesis based on it's seal strength. That's completely bogus and anyone that claims otherwise really needs to do some more homework before they go spouting off any info to the contrary. Everyone I see pushing 20-30 psi in a 13B has a built engine that uses different apex seals and other strengthening items so it isn't all that special in this area either.

Most of the highest horsepower rotaries ever built have been side intake port engines. I agree that the side exhaust shape is terrible but fortunately we don't have to leave those alone. There's more to making power than flow as the Renesis exhaust ports show. Timing has a large effect on it as well. The peripheral exhaust ports had too much timing in relation to the duration of the intake ports. I don't see power being held back as a result of the side exhaust ports either. I think too many people are wrongly speculating what the biggest issue is with making big power on a Renesis and that is quite simply a high compression ratio. That's it's ONLY issue!

This isn't to say that you can't make big power on a high compression ratio engine. You can but you need to know how. This is another problem for most people. There are more bad tuners out there than good and a lower compression engine has more tolerance for stupidity. That's the single biggest challenge to overcome right there! Stop letting people who don't know anything tune these things. You'll see FAR less of them blowing up.

The easiest and most obvious thing to do to make big power on a high comression engine (aside from using a competent tuner) is to use higher octane fuel. I know that people don't want to run around with 107 octane in their daily drivers but then again how many RX-7 people do we see at the 400 hp mark that dyno with it and actually do use it? They definitely exist. When you get right down to it, the more comparisons that are made between the 13B and the Renesis and the amount of power people get out of a Renesis with it's higher compression vs a 13B with lower, it really speaks well for the Renesis and poorly for the 13B. It should. The Renesis is superior in every way. It's like comparing a current Chevy LSX engine with a 90's LT1. It's not even a comparison. Of course I'm comparing the Renesis to a side intake/peripheral exhaust port 13B and not a full race engine. We see people everyday blow up 13B's at 300 hp even with low compression rotors yet we see Scott taking Renesis engines up near the 400 hp mark with their high compression and pump gas. It's a big accomplishment to hit 400 hp in a 13B and above that people are building their engines stronger with the sole purpose of doing it. No one just boosts a 13B up over that mark and expects it to live long. The Renesis is no different. If you want 600 hp, don't expect to be able to do it on a stock engine and if you do, don't expect it to live long.

 

^^ In summary; run away, run away!!!

 

LMFAO stock motor holding 600 horse 13B on tunning alone wow

 

Ari at Rotary Performance did it 7 years ago. He was running a stock Mazda remanufactured block with 26 psi and a 75 shot of nitrous. VERY good tuning through a Haltech got him 620 rwhp and this was the first setup to get him in the 9's in the quarter mile! He raced that engine for an entire season and never blew it up. He did break many other parts on the car though.

 

LMFAOOOOOOOOOOOOOOOOOOO DUDE do you even know what your talking about that's ******* unheard of and on top of that you add a haltech the rotary killer holy **** man stop smoking what ever your smoking and FYI i know ari and raced a full season in a diff class so i know that **** doesen't hold