When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
well it’s overlap in the sense that combustion gases are going to be diluting the intake mixture. It’s also potentially cooking the oil seals.
Cut-off Seals and other newly designed seals
The RENESIS engine has its intake and exhaust ports located in the side housing. With this configuration, blow-by of gases tends to occur between the intake and exhaust ports via the slight gap between the oil seals (corresponding to the piston rings in a reciprocating engine) and side seals on the rotor’s side. Under these circumstances, even in the absence of timing overlap between intake and exhaust ports, retention of some exhaust gas for the next intake cycle cannot be pre- vented. To solve the problem, RENESIS employs an additional cut-off seal located between the oil seals, to ensure almost total elimination of blow-by owing to its tight sealing efficiency. This newly developed gas seal was the technological breakthrough needed to allow the successful design of the side exhaust port engine, and it was achieved through the use of MDI (Mazda Digital Innovation) which allows the use of the same 3-D data from planning through to production, innovative measur- ing technology for strict inspection and analysis, sophis- ticated systems aimed at high-quality manufacturing, and a flexible approach to problem-solving.
well it’s overlap in the sense that combustion gases are going to be diluting the intake mixture. It’s also potentially cooking the oil seals.
Cut-off Seals and other newly designed seals
The RENESIS engine has its intake and exhaust ports located in the side housing. With this configuration, blow-by of gases tends to occur between the intake and exhaust ports via the slight gap between the oil seals (corresponding to the piston rings in a reciprocating engine) and side seals on the rotor’s side. Under these circumstances, even in the absence of timing overlap between intake and exhaust ports, retention of some exhaust gas for the next intake cycle cannot be pre- vented. To solve the problem, RENESIS employs an additional cut-off seal located between the oil seals, to ensure almost total elimination of blow-by owing to its tight sealing efficiency. This newly developed gas seal was the technological breakthrough needed to allow the successful design of the side exhaust port engine, and it was achieved through the use of MDI (Mazda Digital Innovation) which allows the use of the same 3-D data from planning through to production, innovative measur- ing technology for strict inspection and analysis, sophis- ticated systems aimed at high-quality manufacturing, and a flexible approach to problem-solving.
Yup, that info is similar to what’s in the 2004-01-1790 SAE paper, if not the same. Thx for sharing. Anyway, the cut-off seal was the answer to Mazda achieving zero overlap, thus reducing EGR, improving combustion stability and ultimately improving fuel economy/emissions. All of which are meaningless to me. There’s no mention of the cut-off seals reducing blow-by or adding add’l protection to the oil seals/o-rings. I do think they help mitigate those specific issues more so with the 10:1 rotors but I’ve had no issues running without them with the 9:1 rotors.
Granted, I do primarily run open exhaust, E85/M1 among other things and I don’t exactly expect my motors to last 100k miles, maybe 2-years/5k miles, whichever comes first.
Yes, it’s from the SAE paper. It says the opposite about blowby if you read it closely. Pettit specifically machines a groove and adds a custom cut-off seal on13B rotors intended for low compression Renesis turbo use. I’d prefer to have it myself.
Turblown are saying there were minor issues and dyno is any day now ...any updates JETS3T8 ?
It’s about a week away from initial dial-in dyno session, then it’ll go back on the dyno for full pull tuning. Working with Fueltech on a potential upgrade to their FTSPARK-4 ignition system if the current setup isn’t sufficient for M1 and 750HP. Dial-in dyno session results will determine whether or not the upgrade will happen. Also, adding a second 5GPM fuel pump in the meantime.
On another note I’m seriously bummed I didn’t make Sevenstock 22. I worked through the night to sunrise to try to make it happen...on the trailer but it was too little too late...
Big shout-out to gregs for doing what he could to help me try to get the car there. Next year...
Last edited by JETS3T8; Dec 22, 2020 at 12:58 PM.
Reason: Privacy matter
What were the "more than promising" results you alluded to earlier ? I really do hope you succeed but I'm struggling to see how you can even approach the hp goals you have talked about here.
Lol, on pump gas?!
The SXE369 is almost identical to my GTX4294R, 70mm is too small though for 95+ lbs/min. Compressor discharge temps would be stupid 🔥Impressive though.
The plan is to see how well the 70mm does with the new setup compared to last time, then swap in a 80mm GTX4709R Gen2. The 80mm is what I’ll ultimately run at the event in Texas at the end of March.
Fuel system is done.
8x 220 lb/hr injectors and a 5GPM brushless fuel pump. At 2.0 bsfc and 60psi base fuel pressure that should be good for approx 750whp on meth.
Lol, on pump gas?!
The SXE369 is almost identical to my GTX4294R, 70mm is too small though for 95+ lbs/min. Compressor discharge temps would be stupid 🔥Impressive though.
The plan is to see how well the 70mm does with the new setup compared to last time, then swap in a 80mm GTX4709R Gen2. The 80mm is what I’ll ultimately run at the event in Texas at the end of March.
he later clarified it as E85, technically pump fuel I suppose ... it only stopped there because the turbo was maxed out I seem to recall that he reported some fairly low EGT values, but it might have been at lower boost values
looking forward to your own results. It will be interesting to see if you can get the Renesis to breath well enough for that power level.
Well the amount of fuel, flames and rubber that Elliot put down that weekend between my car and Rob's car...ok, mostly Rob's car...was stupid enough to more than likely break or melt something. But nah, wasn't me.
Just want to add that Phatbotti is an absolute brilliant dyno/tuning facility. Ron and Kenny know what they're doing and it clearly shows. They're also very cool dudes.
Now if they only had a backup AWD Mustang dyno... hint hint...
LOL
Perfect timing scrolling through the endless TikTok cat videos.
So NZ was supposed to lower its Covid lockdown level today so that specific sectors could go back to work including TTi, yeah that didn't happen.
Extended one more week so no gearbox yet: https://www.theguardian.com/world/20...down-in-a-week
So might as well take advantage of the downtime to pull the entire rear suspension/sub-frame and most of the front to get it ready for all the new stuff to go in. Not fun.
I seem to recall that he reported some fairly low EGT values, but it might have been at lower boost values 
