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I know this gets asked a lot but I see lots of varying answers, from expecting to only get MAYBE 15 extra horsepower at the crank, to other people saying you can get 250WHP no problem.
My expectations are not high. Id just like to see 200hp at the crank, MAYBE 200 at the wheels, but Im not really married to it.
-I do not want to go turbo. I have a turbocharged car as my other toy right now and I just don't like turbochargers. I'm choosing to go N/A because I much prefer it in terms of driveability.
-Im willing to spend a little money. If it gets to the point where were talking >$10k I might have to set my sights lower (Im a mechanic by trade so labor costs are nil, just my sanity)
-The only part of the engine I'm married to right now are the irons, since I had those refinished and renitrided before realizing there were possibly better options
-I can 100% put S5 rotors in this engine, and am already planning on RX8 stationaries.
-I was planning on following the guide to porting my intake manifold on here, but if an S5 intake manifold would be better than a ported S4 I have no problem getting one.
-I would like to keep the 5/6 actuators functional since this car is going to be a street/track deal.
Right now im planning on full header back RB system, with the presilencer that keeps the actuators functional, S5 rotors, TurboII housings, or just exhaust sleeves, Cleaned and flow tested injectors, Walbro 255 pump, porting the intake, and probably a 4.3 rear end, maybe a 4.77 if I could find one and have my buddies R&P shop weld the proper shaft on it.
This engine also has manual steering, no A/C, an E-fan, and no emissions so the only parasitic load are the water pump and alternator.
Does this sound reasonable? or are the people right who say nothing REALLY helps and at most you're looking at maybe 15hp or so before you have to turbo swap?
the thing that really helps is to be able to try different exhausts/intakes/timing fuel etc.
Modest build, decent power, lot of stuff I'm already planning on, running S4 rotors it sounds like...Sounds like 200 at the crank is fairly attainable. I'm not super enthused about wiring open the 5/6s but I feel like if you open them up to get rid of that pesky overhang that it wont affect it too much to leave them functional. I wonder where these "250 whp is easy" guys come from then. This sound fairly max for an N/A without some serious work.
With a lightweight flywheel and a better ratio rear end, I imagine this would be fairly quick enough. My Saab Viggen makes 230 to the crank, but also weighs a hair over 3100lbs, is front wheel drive, and has serious power reduction in first and second to try and tame the horrendous torque steer. They force power to almost half in first gear, terrible.
I also know that my current engine is NOT making full power. Definitely having fueling issues, engine is for sure starting to get tired. Most of this is happening down the line though.
My goal for this car, as silly as it is, is air cooled 911.
I work on Porsches at an independent shop, and I just absolutely love how raw and simple the older 911s are. You really are 100% in control, the car doesn't help you at all. Its a raw, pure, unadulterated driving experience. That's why, despite everyone telling me it will no longer be streetable, Im putting 14:1 manual steering and deleting the power brakes, putting a heavy clutch in, as well as not going turbo. I understand it makes the car "tougher" to drive, but that's whats beautiful about it to me, is you have to DRIVE it. You can't just lounge back and one hand it around down. You have to be locked in, focused 100% on keeping this car under control. Ive already got the rack in and now I hate the P/S in my other cars. I pulled the vacuum boost for the brakes and while its still not the same, It feels so much more responsive. So right now Im just going through the suspension and such, Making everything as tight as it can be. Engine will be either after im happy with how it drives, or after my current engine kamikazes.
high control effort and difficult to drive fast are different
i'd put a regular clutch in, but you're 100% right about the power brakes, they feel like crap, the FC actually works pretty well too, remove everything plastic, and you have race car...
if you treat the Rotary like a Porsche, it'll make a lot of power, and run forever
Does anyone still make intakes or ITB kits for
these things? I feel like I’m watching the power numbers drop each year as more and more products become unavailable...
ITB's. Those will get you where you want to be without going large bridge or peripheral port. I've ran ITB's and a variety of exhaust/intake combinations before going peripheral port, and managed to net nearly 180whp on a 90k mile stock port s4 block (~216 crank). If you have any questions on my prior set-up, I'd be happy to help
Does anyone still make intakes or ITB kits for
these things? I feel like I’m watching the power numbers drop each year as more and more products become unavailable...
.
remake the lower and upper intake manifold, throttle body goes were the acv valve is, and run 4 short pipes to each intake runner. 3 inch middles, 5 inch on the outside runners. thats the 200hp bottle neck. copy rx8 port deseign over to fc irons, use s4 turbo middle iron for flow.
That looks incredibly enticing. Obviously you're gonna need a standalone to even run this type of setup, what do you guys recommend? PowerFC?
Yep will need a standalone. Which one is a good question that I thought I had figured out and had decided on the PowerFC. The more I read now it seems it was good back in the day and with Banzai Racing's harness it seems fairly plug and play but it seems the general opinion now is it's antiquated and the newer ones have more to offer for not much more money. I'm currently torn between the Haltech Elite or the Fueltech. There are some high boost/ high horsepower rotaries running both systems so controlling a n/a shouldn't be a problem with either one. Ask five people you'll probably get five different answers. Sorry that may not be much help.
See, now that Haltech Elite price is quite a bit up there, and I cant help but wonder if that would be a bit...excessive? for a 200hp N/A setup...I could probably get away with a E6X or PFC or something right? Im not planning on ever taking this much farther than 200whp unless 250 or so ever becomes the new normal (Which considering nobody is even building 13bs anymore and all the youtubers and rotary guys are going 20B now, doubt it)
Also with the 2 ITB ports provided on the RB intake, would that be enough to hit the 200whp target? Or do I have to think more like making my own intake and running 4 ITBs?
See, now that Haltech Elite price is quite a bit up there, and I cant help but wonder if that would be a bit...excessive? for a 200hp N/A setup...I could probably get away with a E6X or PFC or something right? Im not planning on ever taking this much farther than 200whp unless 250 or so ever becomes the new normal (Which considering nobody is even building 13bs anymore and all the youtubers and rotary guys are going 20B now, doubt it)
Also with the 2 ITB ports provided on the RB intake, would that be enough to hit the 200whp target? Or do I have to think more like making my own intake and running 4 ITBs?
It depends on which one you get. The Elite 2500 is pretty high, but the 1500 with universal harness is like $1658. By the time you buy the adapter harness for the PowerFC and the extra trailing coil you're at $1440 if you get you coils for $75. That doesn't count the adapter and software to connect to a laptop which adds $265 more for a total of $1705 for a PowerFC. That's all new pricing( except the coils) to keep it apples to apples.
As far as the ITB goes there are people making more than 200rwhp with peripheral port motors and two ITB's so it should be fine for you're application.
P.S. as long as you don't plan to go 3 rotor you shouldn't ever outgrow the Elite1500. You might be able to get away with one of the cheaper ones even.
It depends on which one you get. The Elite 2500 is pretty high, but the 1500 with universal harness is like $1658. By the time you buy the adapter harness for the PowerFC and the extra trailing coil you're at $1440 if you get you coils for $75. That doesn't count the adapter and software to connect to a laptop which adds $265 more for a total of $1705 for a PowerFC. That's all new pricing( except the coils) to keep it apples to apples.
As far as the ITB goes there are people making more than 200rwhp with peripheral port motors and two ITB's so it should be fine for you're application.
P.S. as long as you don't plan to go 3 rotor you shouldn't ever outgrow the Elite1500. You might be able to get away with one of the cheaper ones even.
Ill go 3 Rotor when they pull my lottery numbers lol.
I seen that guy on the dyno sheets page pull 170 on stock ports, S4 internals, and exhaust baffles, so I have to imagine 200 is achievable with a street port, S5 rotors, and exhaust inserts.
I'm currently using a custom two runner intake manifold with one set of 48mm Jenvey ITB's on my peripheral port. This is currently making around 270whp with a Haltech E6X.
When I was on my stock port S4 engine, I used a DCOE style two runner intake manifold and one set of Racehead.au 45mm ITB's. This made 170whp with a Haltech E6X. 200 should be achievable with those components and the mods you've mentioned.
While cost is a factor when choosing an ECU, I've learned it's best not to cheap out. Do you want to fiddle with your idle, coolant temp, and air intake maps every time the seasons change? What about if you encounter a severe change in elevation? It gets annoying and despite still using the E6X, it definitely has it's shortcomings. Aftermarket ECU technology has come along way in the last 10 or so years, and adaptive tuning capabilities are the bees knees.
I'm currently using a custom two runner intake manifold with one set of 48mm Jenvey ITB's on my peripheral port. This is currently making around 270whp with a Haltech E6X.
When I was on my stock port S4 engine, I used a DCOE style two runner intake manifold and one set of Racehead.au 45mm ITB's. This made 170whp with a Haltech E6X. 200 should be achievable with those components and the mods you've mentioned.
While cost is a factor when choosing an ECU, I've learned it's best not to cheap out. Do you want to fiddle with your idle, coolant temp, and air intake maps every time the seasons change? What about if you encounter a severe change in elevation? It gets annoying and despite still using the E6X, it definitely has it's shortcomings. Aftermarket ECU technology has come along way in the last 10 or so years, and adaptive tuning capabilities are the bees knees.
270rwhp out of a PP? Sheesh. The fact that those numbers are achievable N/A is honestly a load off because I was so worried I was gonna have to go turbo.
what else did you do to make the 100whp jump? I can’t imagine just the PP did that.
having run all the haltechs at one point or other, i would not use anything older than the platinums. so the E6A,s,k,x, E8, E11's all can just go in the round file, its about all they are good for... the platinum and elite are ok.
Power FC is nice, but its in Japanese or you need to buy more stuff to tune it.
Adaptronic had a plug in ecu that would work, megasquirt is an option too
270rwhp out of a PP? Sheesh. The fact that those numbers are achievable N/A is honestly a load off because I was so worried I was gonna have to go turbo.
what else did you do to make the 100whp jump? I can’t imagine just the PP did that.
Going PP is a huge advantage over stock port style engines. The amount of air flow is drastically increased (as is the amount of fuel needed) and yields much more power than nearly all standard side port style engines can offer in NA format.
To be honest, these are the only major (power affecting) things I changed between my stock port and PP engine:
Switched from 45mm to 48mm ITBS
Custom intake manifold (slightly shorter than my old Star Mazda one)
Switched from 2 ID1000 injectors to 2 ID1700x injectors (kept maxing the 1000's out)
Upgraded fuel pump to a Walbro 255lph (kept maxing it out)
S5 rotating assembly with modified Rx8 e shaft and stationary bearings
I even kept my Racing Beat true dual exhaust on both engines. Although, it's definitely restricting power on the new engine and will be tossed shortly.
What would the true dual be doing to restrict the power? Asking because I'm going to pick up a nice used dual exit RB power pulse catback this weekend. I was looking at a CorkSport one, but I also want to be able to somewhat drive this car on the street and don't want to be getting tickets left and right for sounding like a goddamn 787B. I suppose I can always sell the RB if I out grow it but just out of curiousity. Are those 2.5" pipes vs a single 3" or something?
What would the true dual be doing to restrict the power? Asking because I'm going to pick up a nice used dual exit RB power pulse catback this weekend. I was looking at a CorkSport one, but I also want to be able to somewhat drive this car on the street and don't want to be getting tickets left and right for sounding like a goddamn 787B. I suppose I can always sell the RB if I out grow it but just out of curiousity. Are those 2.5" pipes vs a single 3" or something?
In the case of a peripheral port, you really need to collect the exhaust to get the most power possible (the collection point changes based on desired powerband and torque vs peak HP). The true dual never merges into a collector, so this is inhibiting performance in my application.
FWIW, I did back to back dyno testing with an RB true dual and a custom collected exhaust (using the RB true dual header) and I made ~11 ft lbs more torque and a handful of hrsprs (torque being the focus). The other benefit of the collected exhaust is you can lose a substantial amount of exhaust/muffler weight, which I deem important when building an NA car with lower power. Here's the dyno results:
I actually work for CorkSport now, lol. The old exhaust systems were definitely loud.
What would the true dual be doing to restrict the power? Asking because I'm going to pick up a nice used dual exit RB power pulse catback this weekend. I was looking at a CorkSport one, but I also want to be able to somewhat drive this car on the street and don't want to be getting tickets left and right for sounding like a goddamn 787B. I suppose I can always sell the RB if I out grow it but just out of curiousity. Are those 2.5" pipes vs a single 3" or something?
The catback is a different setup than the true dual. The true dual never collects the primaries which if I understand correctly works good on stock ports but isn't the best setup if any porting has been done. Stainless Steel Road Race Exhaust System for 86-88 RX-7 Non-turbo - Man Trans - Racing Beat The catback bolted to the rear of the cat which is a single outlet the splits via a Y-pipe to the dual mufflers http://www.racingbeat.com/RX7-1986-1...sts/16418.html
If I were starting from scratch on a n/a system I would use the road race header and pre-silencer from the true dual system then depending on whether I wanted to keep duals or go single would determine where I collected it. The single should in theory make the most power because you can collect it further back. If you want to keep the dual outlets you can collect it mid chassis. In theory it would produce less power but how much I'm not sure. To hit 200whp you probably have to tune that collection point on the dyno anyway.
As a side note this car made 227whp with a RB catback.. Primary lengths were never disclosed. Also it's a 13B-RE block. From all I've read I'm not sure a 6 port will ever make those numbers. https://www.rx7club.com/naturally-as...1032737/page3/
P.S. The guy who built that engine's personal car made 230whp with almost the same setup and a mid collected exhaust so who knows. I think it comes down to what each engine wants when it gets tuned on a dyno.
...The other benefit... ...is you can lose a substantial amount of exhaust/muffler weight, which I deem important when building an NA car with lower power.....
with the NA car i like to take an approach that looks at the whole car. its really easy to loose 100lbs from an FC, its easy to gain ~20hp, its easy to make some suspension adjustments and get much better handling, and separately none of those things makes much difference, but put them all together and the car feels completely different.
Some good info in here. Best of luck! I am also trying to get 200+rwhp out of my NA S5 motor. Half bridge ITB’s. Got these ITB’s from EFI Hardware. They make a lot of great stuff!
04-27-20, 10:56 AM
