t-von

iTrader: (8)

For the life of me, I dont understand why Nissan hasn't put in a detuned version of the GTR engine making 400hp? No room in the engine bay?

BLUE TII

iTrader: (9)

The reason people love the GT3/911 is because of the commitment and refinement that's poured into it. I don't like rebuilding my cars from scratch which is what you have to do with the FD in order to run a fast reliable lap. The GT3 you just put gas in it

That is absolutely what the GT3 has going for it. Amazing right out of the box.

Sounds like the GT3 needs a better driver if a 240 HP rx8 is beating it. It has much bigger tires, much greater down force and a huge power to weight advantage. Something isn't adding up here.

Well, the GT3 has a skinnier front wheel/tire and wider rear tire/wheel than the 265s that were on the RX-8. That probably doesn't help on a handling course.

I personally put my 18x11 with 295s from my rolled fender FD right on my stock stock RX-8 front and rear and raced. RX-8 swallows wheel/tire.

These are Tsukuba lap records, so they are all done by about the top 6 or so drivers in Japan.

Tsukuba is a tight track that rewards chassis over just raw power- that is the part of the reason it is loved for tuner challenges.

The GT3 would slay that RX-8 on say the Fuji Speedway with its very long straight.

BLUE TII

iTrader: (9)

For the life of me, I dont understand why Nissan hasn't put in a detuned version of the GTR engine making 400hp? No room in the engine bay?

It would be faster than the GTR in some scenarios- can't have that.

Not to mention much easier to wreck.

*cough* shades of Porsche and 911 vs Cayman

t-von

iTrader: (8)

The 20b is dead. Gordon really means 24x. . Me I just say 3 rotor as who knows what Mazda would call the engine if they actually indeed build it.

t-von

iTrader: (8)

If Mazda was serious about it, they could have made the provisions to make it work. Redesigning the firewall would have allowed clearence for the engine and LIM and twins. Then they would only need to make the 20b specific subframe, ppf, and shorter drive shaft. I think it has more to do with them not having any room for the twins. You see when you move the engine back and lower it (as I did in the current chassis layout), to have to center the engine in the engine bay so it tucks into the tranny tunnel. I had to round out my tranny tunnel to create the pocket for the tranny to sit in. The factory rew is biased towards the left side (or drivers side for us USA folks) to make room for the twins, down pipe, and right hand drive steering linkage. Mazda uses the same subframe for both fd's. While doing my swap, I acually tried to see if the twins would fit but, I had no room with the engine centered. Back then Mazda wouldn't have done a NA 20B due to them not having the 20b designed around the NA ideal of using the FC style aux ports. So the fd got stuck with just 1 engine.

Now Mazda has already made those firewall provisions with the new Miata and those same provisions should carry over to the next Rx7. Anyone notice that nice deep pocket on the firewall? That's how they got that long 4 banger to sit behind the factory front wheels. That 4 banger is about the same length as a 20b so even a 20b would fit nicely in the new Miata chassis.

t-von

iTrader: (8)

^Gordon I think a 24x could make higher than 375. Don't forget that on NA's rotary's that the output is very proportional to the displacement. Mazda has claimed that the 16x can make up to 300hp with emissions in place. That's 150hp per rotor. So a 50% larger displacement 3 rotor would potentially max out at 450hp (provided they both have the exact same designed intake and exhaust length setup). Actually the 3 rotor would make slightly less because it would be too tricky to engineer a VDI system to manage the intake pulses between 3 different rotors. VDI ususally adds 20 extra hp so 430hp would be a better guess for a 3 rotor. Either way that much hp with maybe somewhere around 350lbs in a 2,800lb chassis would be more than enough to handle that Gt4 while drinking 87 octane. Plus this torque range means the drivetrain wouldn't have to be over built (which makes it lighter).

t-von

iTrader: (8)

I dont know what your engine makes but there are some examples out there to help do the comparisons. For starters your average PP 13B makes 300hp at 9k rpms. 13G with similar intake makes 450hp. 4 rotor 600hp. You build the engine to spin higher, you make more (as Logan had done) if the intake is designed to move the torque curve right. Do you remember Logans side port Cosmo engine in his 1gen? It's the most hp I ever seen out of a pure side port and I think it made 230rwhp. That's 115rwhp per rotor. That engine had a shortened LIM and stock UIM. Years later while he was experimenting with his semi pp 20b, he did a dyno run with those ports caped off, a similar shortened LIM, and stock UIM and made around 350rwhp. That's still in that 115rwhp range. Now there will always be variations but for the most part both engines were built to the same standard and the 50% larger engine made 50% more power.

Now the newer engines would be no different if there NA. The biggest mechanical difference with the new engine compared to the old engine is the newer engines longer stroke. I have NO idea how much that will effect torqure but if will be an increase everywhere in the rpm band. How much of an increase is anyones guess until we see some official numbers. Whatever a 16x makes, those numbers can transfer to a 24x as both engines will share the same basic mechanical geometry.

ptrhahn

iTrader: (9)

Normally I'd say if there's a hole in the market, that's what you would exploit, but at least in terms of cost, it's starting to look like there's a hole... sort of like how they don't build any regular/medium sized homes anymore, just condos and McMansions.

You've got the cheap/simple segment at $20-$30k (Miata, BRZ), and you've got the high performance segment starting at $50k and up. The 370Z is stuck in the middle. It's neither cheap nor really fast, and it doesn't sell well. Buyers either want to go big or go home.

I think this dictates the new RX7. It's never going to fit in the "cheap" segment... people in that segment are largely going to rely on a safe easy piston motor and, and probably should. So, make a 50k+ car that kicks ***, or expect it to sell like a less-reliable 370Z.

That DOESN'T mean you have to tackle the problem the same way (i.e.: out-corvette corvette, or out-mustang a mustang). You've got to create something that performs (by some definition) well enough to be desireable at that price level. Mazda's combination of uniqueness, power, light weight, chassis design and looks COULD work without being a Japanese Corvette.

Fritz Flynn

iTrader: (263)

The exact car we have been talking about is the GT4. Currently sold out and just weeks after the announcement.

If mazda builds a 400 HP 2800 pound good looking sports car they will have buyers despite it being a Mazda especially if it cost 20k less than the p car. IF for some crazy reason they put a 3 rotor in it they won't be able to make them fast enough because that's a super cool engine. HOWEVER they don't have the *****, the current cars are lame and that includes the new miata

The 600 HP 3600 pound cars are cool but weight really does matter more than power when it comes to sports cars especially when considering them for track use because the heavier the car the more your operating cost go up; brakes, tires, gas etc...... More importantly light cars are just way more fun to drive.

j9fd3s

iTrader: (3)

have you seen one? its packed so tight, it makes the FD engine compartment look like ranch land in montana.

and as is they are useless at the track, it goes 2 laps before the brake are cooked, and the engine is running hot.

HiWire

Would other changes to the engine have a significant effect on power or efficiency (e.g., lighter rotors, lower friction coatings on facing parts, ignition, etc.)? I'm sure most exotic things have been tried before somewhere, but there must have been significant advances in some areas of manufacturing in the last 25 years that are beyond the resources of hobbyists like us.

j9fd3s

iTrader: (3)

the 911 is a double edged sword, its like if you went to a Duran Duran show and they didn't play Girls on film, or Rio, nobody would leave! or maybe Led Zeppelin without stairway.

if we flip through our history book, we would that sometime in the 1970's the upper management at Porsche considered the 911 a dated relic, as the 928 (don't laugh, its actually true), and 944 were better cars. they cut the 911 development budget to zero, and were waiting for sales to die off to kill it.

since Porsche is more of a religion than a car company, the faithful refused to accept their new icons, they were deemed heretical, and thus after a rather shrewd business meeting, the 911 emerged from its cave born anew.

so the 911 is a double edged sword, Porsche has developed it to a point where its excellent, although it isn't by their choice

Fritz Flynn

iTrader: (263)

It's a religion based upon a cool car that's very reliable, fun to drive and looks great. That's a good religion for all car companies to believe in. And no doubt back in the early 80s when porsche moved into a different religion the faithful didn't follow.

This is why an RX7 with a piston engine or something that looks like the new miata will likely not do so well either. Mazda needs to swing for the fences and if they hit a grand slam great and if they strike out well at least they stepped up to the plate and didn't bunt the damn ball like they've been doing.

t-von

iTrader: (8)

Lol sounds like a piece of sports car junk.

t-von

iTrader: (8)

For the most part there will a tiny increase when you reduce friction however, the largest increases come from more rpm and an intake and exhaust designed to around that rpm. That's when lightend rotors come into effect. Lightened rotors also have the same effect as light weight flywheels. They just make the engine more responsive and rev faster. They also lessen the loads on the eshaft and stationary gears at high rpms. The traditional problem with moving the torque peak farthure to the right is lossing a TON of torque down low. Torqueless street cars are no fun to drive on the street. Moving the torque curve to the right also involves introduction of more overlap into the engine. As soon as you start introducting more overlap, there goes your emissions.

t-von

iTrader: (8)

I'm sure your engine has a consideral amount of over lap to help make the power you wanted. That overlap eliminates the refinement and causes that lumpy idle his engines are known for. There's ways around this and that's why i've built my intake and mid exhaust section the way I did. My engine has no overlap until my secondaries open. If you want refinement, it is very important to have a functioning secondary system in place.

j9fd3s

iTrader: (3)

and its ugly too! so it sells in huge numbers...

Fritz Flynn

iTrader: (263)

Don't be too hard on the GTR

Check the OLOA results and that's enough said

t-von

iTrader: (8)

I'm sure the Gtr is however the 370???? Every year I go to Vegas to the Sema show, I drive the nice exoctis at Exotics Racing or Dream Racing. I've driven a Ferrari F430, Audi R8 V10 and the new C7 Corvette. The Ferrari has been my favorite thus far. I think this year I will try the Gtr and Porche so see what, they feel like.

j9fd3s

iTrader: (3)

Mazda has tried just about everything you can think of, in fact most "new" ideas people propose, are cataloged in Kenichi Yamamoto's book.

however there are two obvious areas for improvement in the rotary. the first is just the basic dimensions, NSU picked the basic dimensions in the early 60's when there were higher speed limits, no emissions regulations, and gas mileage wasn't as big a concern. this favors a high overlap engine that makes power at high rpms.

in 2015 we have emissions regulations, gas mileage is a huge deal, and traffic sucks, this may mean a look at the basic geometry of the engine. the 16x shows that Mazda has already thought about this.

the second area for improvement in the rotary is just that piston engines have enjoyed some really detailed refinement in the last 20 years, in just about every aspect. the rotary basically hasn't had much of that. there are some big potential gains there too. for an example Mazda just studied the flow of metering oil through the engine in 2014.

that all being said, power is a function of airflow, and we knew how to do that already.

if you gave me the thing and said make it work, step 1 is to try a few different combustion chamber sizes, as you need to optimize that first

j9fd3s

iTrader: (3)

i was talking about the Z. the GTR is a whole different ball of wax.

00SPEC

iTrader: (9)

ND miata + forced induction +10,000 to 00SPEC for delivering it to you = way less than 65,000!


let me know if you're interseted

Fritz Flynn

iTrader: (263)

Yes it is but it also only runs two hot laps before overheating, throwing codes etc... until you set it up and then DAMN!


The Final Minutes Of The Bathurst 12 Hour Is The Best Racing All Year

rx7 SE

iTrader: (5)

Was the OLOA the event you were planning on competing in last year? Be nice to see some properly prepped FD's take the fight to the GTRs. The FD still has yet to be beat on the Touge in Japan, that includes beating R35s IIRC.

t-von

iTrader: (8)

^I haven't seen the fd beat there yet also.