jkstill

iTrader: (11)

It just might have something to do with that 3rd rotor.

I don't claim to be an expert, but the idea that the rotating assembly supplies the torque sounds like the same argument often used for flywheels, that a heavier flywheel will create more torque than a lighter one.

Here's a discussion about the weight of rotating assemblies:
https://www.rx7club.com/rotary-car-performance-77/lightweight-rotors-%3Dmore-horsepower-less-torque-104318/

Torque is a function of the length of the lever applied to the crank.
Longer lever, more torque. I know that is over simplified but in general that's the case.
http://auto.howstuffworks.com/question381.htm

Having more applications of power to more levers (3 rotors instead of 2) will also increase torque.

no_more_rice

Correct, heavier flywheels can improve the usable spread of power, but they don't improve torque output.

Interestingly, I test drove a friend's 430 rwhp C6 this week, and, although the LS3 pulls great from down low, it doesn't feel any faster than my FD....I went away feeling better about my car and my current set-up

Herblenny

iTrader: (13)

I didn't read everyone's posts.. just select few...

My opinion is that I personally don't give a damn about HP.. I care more about can I feel confident driving it.

I'll be honest, I've done few track days (when I first bought my FD back in the days and when I bought my 8 couple of years ago) but I could tell you that even in my 8 (making less the 200wrhp) I made too many mistakes to call myself a good driver. I mean, anyone can go around the track and say you did a track day, but did you really learn the max potential of the car?? I say no. To push 500RWHP car to the limit will require an experienced driver.. which to start from limited experience with 300 or 400 to move to 500+ is just not so smart. I'm sure some of you are just better driver from start, but I can't imagine even pushing my maybe low to mid 300+ RWHP FD at a track. I on the other hand don't mind if people want to just say, "I have a show car and made 500+HP" or "I only do straight line pulls and love my 500+HP FD". But this topic is, is it more enjoyable?? I don't think so... Seems it will catapult you faster but is that what we call more enjoyable?? Otherwise, putting 500+HP during a turn will just make you **** on yourself as you come closer to a tree or off of a cliff. Which, I don't consider enjoyable. A good balance where you feel comfortable to your level will give you that enjoyable level.. My opinion.. its to each one of us.. But I think some of you might be lying to yourself if you think you are that good of a drive to say 500+ RWHP FD is that level.

PS... I'll be honest... I've always kept from going single because I felt I had no need for it. I love the twins and way it works and how responsive it is. I even have a T76BB and a manifold I could of put on, but I just love how my FD drives.. I will however will be installing a 3rotor single in it, but I don't think I'll enjoy it as much.. Hence I'm going to have a more steetable FD on the side.

no_more_rice

I haven't driven the Lotus yet, but the S2000 feels more agile than the FD. It's underpowered but fast enough for daily commuting and well suited to the task

Slevin_FD

iTrader: (26)

Yet another wild and dangerous idea from me. Besides BNR has anyone, any where tried to produce larger twins I'm asking because I'm thinking What IF there were larger twins out there that could still net you say 450.... I know the BNR's are capable of getting close to that at least the 20'B twins. But if I'm not mistaken they aren't sequential anymore in order to do that.

ALPSTA

iTrader: (3)

I know someone who told me he has a twin set-up which has something like a GT28 and a GT30 together. However I'm not 100% on this cause it's been a long time, we've talked about it and I remember him mentioning this without going into detail. I will talk to him and try to find out the details.

jkstill

iTrader: (11)

Howard Coleman runs Twin GT35R's in his FD.

A few minutes searching should turn up a picture of it here somewhere.

Or maybe Mr. Links knows where it is?

Beast From The East

Sadly we lost Kevin Wyum recently, who along with Brooks Weisblat was a true pioneer in our FD modification arena. He had the best 'true twin' setup, with 2 individual manifold singles. I can't begin to describe his set up, you'll just need to search on his name to find his threads....but he's one on just a handful of folks to really develop a true twin system that was out of this world.

As far as chassis reinforcement, and the front strut towers in particular, I don't think I've seen any threads on this because once you get to this level, you start to do a lot of custom stuff that is unique to your particular setup. I have the benefit of access to Cam Worth and some other knowledgeable racers that have done this and will get the benefit of their input, but basically you acid dip the front clip to get all the dum dum sealer off, you seam weld everything, and then just like a roll cage you start using angle iron and tubing to make triangular reinforcements to the towers - you can make them standalone, or penetrate the firewall and tie them in to your cage. You basically start turning your car into a semi-tube frame.

All of this turns your car into a track only machine. You only need to do this if you have reached upper regions of bhp on your car, and are using R compounds or racing slicks that apply the forces back to the chassis. You likely won't need or benefit from any of this if you stick to the 'mild mod' of a street FD with twins, nor even with a 500+ bhp FD if all you do is use it on the street and do straight line blasts.

Getting off topic now, sorry. Original thread was on 500+bhp for street. For me, no thanks, but for my race car, you bet....but I won't dial up the wick to 20 lbs boost (which will get me to 450 or so on the standard T04S that I have) until I have a lot more areo on the car, and I'll use slicks vs. R compounds. I'll have to run in the Unlimited classes with that much power, so after that you can do slicks and penetration of the firewall etc.....for now I'll keep it at 16 to 18 lbs of boost running in the high 300 to 400 bhp range and be very happy - still more car than I have skill to handle...yet

Some info on seam welding for Miatas, applies to just about any car:

http://www.flyinmiata.com/tech/seamweld.php

as far as custom penetration welding for shock towers and pickup points, you'll have to search around, look at race fabrication shops and rally car builds, they use this a lot given the abuse they take.

Wargasm

The S2000 (both engines) is a GREAT car. Awesome handling and enough power for anything except drag racing.

In case anyone was wondering - which is better - the 2000 with the 2.0 liter 9k RPM engine or the 2007 S2K with the 2.2 liter 8k engine.... Here is my opinion.

2.0 liter car
-------------
Pro - 9k rpm is awesome
Pro - Smaller 16 inch rims and tires (also skinnier) make the car very fun to drive like a stunt man hanging the tail out and power sliding. Very fun.

Con - No torque. Don't drive it like a wimp and you are OK.
Con - Older cars had plastic rear window which cracks and clouds up.
Con - No clock and no storage (not a big deal to me really)

2.2 liter car
-------------
Pro - More polished design. Updated bumpers and accents.
Pro - Has a clock, a tiny bit more storage, GLASS rear window.

Neutral - Bigger engine has more torque (still almost none). Same peak HP. Redline dropped by 1k.

Con - Bigger rims and tires actually make the car LESS fun in some ways. It is very hard to spin the rear tires now since they are so meaty compared to the meager torque (245 width).
Con - Stability control system is ON by default. LAME. This thing ruins all the fun. You must disable it every time you drive.
Con - Clutch slave has a bleed valve in it to prevent hard clutch takeup. They went overboard on this so you can't even shift hard without burning the clutch some. LAME. This + fat back tires = much harder to induce power oversteer compared to old car.



Lotus Exige - Wow, great car with one problem. No power. It is better than my FD or my S2000s by leaps and bounds in terms of steering feel, cornering, turn-in, balance, looks, cool-factor.... etc. It just needs like 200 more HP. I could tear around corners in that car at speeds that you would swear you could never do. Coming up on a turn and you're thinking, "oh my god, I'm coming in too hot - ****", and then the car just sails through the turn like you were driving like a grandma. Seriously if I had a Lotus Exige with ~275 rwhp, I would never drive my FD again.


The RX-7 stacks up very well (and I think is still better handling than the S2Ks, but not by much). I have driven probably 15 different FDs over the years, and I think a big factor is that many FDs are over 100k miles and 15+ years old. That takes its toll on shocks/bushings/springs. I've driven some really shitty-handling FDs due to wear and tear of the components. I think an FD with a brand new stock R1 suspension vs. an S2000 with brand new stock stuff - it would be almost dead even.

Howard Coleman

iTrader: (6)

"the front strut towers are also just spot welded and THAT is where the chassis begins to suffer"

the front coil over (no struts no where) upper mounts have nothing to do w the chassis w re to handling. the upper and lower A arms call the tune and they are solid. further, most everyone adds a lateral brace to match the mazda item in the rear. the brace has no effect on suspension geometry.

i haven't read this thread but do consider it an interesting subject in that is considers perhaps the most important issue re living w the FD....

where is the line between additional satisfaction and eventual dissatisfaction on the mod scale.

it is so easy to get too high on the mod curve. of course for each of us the spot is differently located.

having owned and raced real racecars for 22 seasons i really don't want/need another racecar that also lives on the street. i am all about dual purpose. it is very difficult to know when to say enough...

for instance, spring rate. i am testing Pettit's new Trak Pro coil overs. i have two sets. the Stage 3 and Comp. the stage 3 came w 12/10 springs and the Comps w 15/10. i have the Comps on currently but switched in the 12/10 springs. while the Trak Pros have a rubber upper mount which does a magnificent job in absorbing shock the 12/10 rate is too much for me. i will probably settle on 10/8 or 8/6. dual purpose. i want to always enjoy driving my FD.

as to HP, the subject of this thread... i have had about 500 SAE hp at 20 psi w my twin TO4 setup for a number of years. i found it just fine to live with. (you don't always need to run 20 psi). that's the beauty of turbos. unlike hopping up a piston engine w a wild cam, really stiff valve springs etc a turbo can do the put put thing really nicely.

there are a bunch of pricey items to do 500. AI, a double disc clutch so you don't have to run 2600+ pounds spring pressure, wheels and tires to keep the rubber on the road, a different LSD (you will shell the Torsen).

the list goes on.

but if you do it right, build it over a period of time, a 500 hp FD is a magnificent beast that can also be a pussycat.

balance is key. find your own spot on the curve... go too crazy and you will end up hating your car and selling it. do it right and you may keep it for life.

hc

ALPSTA

iTrader: (3)

S2000's handling is too nervous imo. In standard form it's a car waiting to spin on you when driven close to the limit, especially on sudden direction changes. Although it's much younger I wouldn't use S2000 in the same sentence with RX7 (oops I just did ) And the only reason it's often compared to RX8 is because Mazda decided to equip a perfect car with a sissy engine.

I have not tested it but I don't think stock RX7 vs. stock S2000 will be dead even. RX7 should beat it in every category (handling, acceration, top speed, touge, autox, drag etc.).

no_more_rice

Isn't the new supercharged close to that number? A turbo rotary Exige would be perfect - Lotus needs to hang it up with that wimpy Toyota engine

The S2000 CR would be a better match, it turns significantly faster lap times, but I agree it would be close

Fritz Flynn

iTrader: (263)

I owned one back in 2001 and would agree. I think the FD is lighter, stiffer, better designed susp, pulled higher #s etc.... Much easier to modify and will destroy an s2k on track.

no_more_rice

Howard, what is your experience on track with 20b powered FDs? My contention is that the 13b is not well suited to track (or mountain road) use because the power delivery of a single turbo FD is simply too peaky/narrow and difficult to manage, regardless of what turbo(s) you're using. One of the guys from this forum I spoke to years ago with a well set-up single turbo said he simply couldn't compete with Porsches at VIR for this reason, and he sold the car.

It's not just the peak number, it's how the engine gets to that number....especially in light weight vehicles

no_more_rice

The FD is marginally lighter than an S2000 and chassis rigidity is basically identical

Wargasm

Ah ya.

Re-reading my post, when I said "almost dead even" - I was mentally thinking for street enjoyment. I guess I typed it badly. On the track it is not as close.

stock for stock on the track I agree that the RX is a step up from the S2k - but most of this will only be noticed on the track. I think the RX has much better (more fade resistant) brakes. The S2000 is fine but for a few minutes, but after that, they get hot and start getting weak. When you start comparing raw numbers like cornering, slalom, top speed... the FD and S2K are not terribly far off and you're really pushing it if you are using either car to 9/10ths on the street. Gotta take it to the track.

*these numbers are from memory so don't flame too hard if I get one wrong heh*

Top speed:
FD -155-160 mph
S2k - 150-155 mph
this won't matter on the street

Cornering:
FD - around .95?
S2K - around .90?
Really I just don't see this coming into play on the street.

0-60:
FD - low 5
S2K - low 6
this isn't huge, but if you like to stoplight race this will matter. This is probably the biggest gap.

Quarter Mile
FD - low 14
S2K - low to mid 14

Slalom
I think both are pretty much the same +/- a few mph.


Getting back to the 2000 vs 2007 differences, the one thing that does annoy me about the '07 I forgot to mention is that it is too "safe" now. Alpsta's comment made me remember this. I *liked* the fact that the older car would snap around more. Yes, you HAD to be careful, but it was great. The new car takes a very determined effort to get the back end moving.

As for the lotus, they do make a 260 hp supercharged version now, but that's engine hp, not wheel hp. It could still use a boost IMO to back up the supercar looks and match the awesome chassis.

Fritz Flynn

iTrader: (263)

I have a mildly powered single turbo FD and the only Porsches I don't compete with are cup cars.

What's this dudes name?

Fritz Flynn

iTrader: (263)

No **** I figured the fd would be stiffer than a convertible. Oh well I'm sure you've done your research but the fd does beat it on paper and it's easier to drive and more fun to drive imo Mod both cars and the FD is in a different class all together.

j9fd3s

iTrader: (3)

you can't compete with the porsches, they can ALWAYS pull out the keychain at parties, it doesn't f-ing matter that they can't drive, and got passed by a honda twice in one 15 minute session....

when you are talking roadracing the driver is very important in the lap time. for instance the porsche guys have two groups, a turbo (450hp) and non turbo (250?) hp, there are about 20 cars in each group.

if we entered our honda 140hp/2350lbs in either porsche group we'd be midpack.

how does a 140hp honda run faster laptimes than 10/20 450hp cars? the driver.

actually, you say its not the peak hp number but how the engine gets that number, which is right. applied to road racing you might say that its not the peak power, but how much time the accelerator spends in the open position.

Zero R

iTrader: (1)

I used to use the analogy of a F40, the car weighs in at 2400lbs with 471hp meaning if a FD has 500whp it is getting very close to the F40's power/weight ratio. A say it all the time a 450-500whp FD is more than anyone really needs to put a smile on their face, it's stupid quick and other than suffering from a ego problem you really don't need much more.

~S~

Rxmfn7

iTrader: (4)

Not to nit-pick, but the S2000 is actually quite a bit stiffer than the FD. Later model S2000 (post '04, not including CR) chassis rigidity is 22,000 Nm/degee. The FD is 15,000 Nm/Degree. And just for comparisons sake, the Rx-8 is 30,000 Nm/Degree.

And to keep this thread on track, owning my S2000 is actually what made me 100% sure that I wanted a ~350rwhp FD with the smoothest powerband possible vs a higher HP car. Ive been fortunate enough over the past few years to drive/ride in some very fast and powerful cars. Most of my friends are muscle car guys, so I have no shortage of high toque V8s. While those are nice, I dont enjoy the powerband all that much, I like revs. The last crazy thing I rode in was a procharged C6 Z06. Ive never felt acceleration like that, even on a bike. While things like this are fun, getting back into my ~240HP S2000, with its 9k redline and being able to pretty much drive it at full potential whenever I wanted, made me realize I have much more fun doing that, even though other cars may be much faster. I guess its true at least in my case, that its much more fun driving a slow car fast that it is having to drive a fast car slower. This may all be personal preference, but Ive realized I dont need/want 500HP to enjoy my car. Not long after I rode in that C6 I got to drive an NSX, and horribly slow by comparison (not any faster than my S2k) Id probably take the NSX over the C6.

ALPSTA

iTrader: (3)

Damn you Mazda, all we needed was a RX8 (2 door coupe no scissor doors) 13b with simplified sequential twin turbo, no rats nest and no million solenoids and then no one would be talking s2000, 350z etc. :P

Fritz Flynn

iTrader: (263)

I agree completely. The S2k is a hoot to drive. I put 5k miles on my S2k car in 3 months of ownership and most of those miles included driving out in the country at night. I loved the lights on that car. I did end up tapping a deer and leaving an H on his hind quarters which was 1800 in damages because those nice headlights are also expensive lol.

However for me a twin turbo FD with some nice coilovers, good set of sway bars and tires that aren't too big (allow for some movement) with 300 rwhp is the perfect DD. I don't think anything else out there would compare other than a GT3 and lets face it as much as I'd love to own one I need a few more gold bars to feel ok with that move.

PS it's amazing how stiff the RX8 is but it's looks are too busy for me.

Zero R

iTrader: (1)

Ha! We had a few turbo elise's here and I know exactly what you mean I got out of those cars going these cars are more RX7 than a Rx7. You described it perfectly. However they are a bit spartan and I could see people being a bit worn out by them if they drove them daily.



When I turbo'd them and had to drive them around you honestly forget the car has no top on it, they are that stiff. They feel as solid or more solid than a FD.

~S~

Fritz Flynn

iTrader: (263)

There's still hope that Mazda will make another Rx7 I just hope it isn't another s2000 but a 300 plus rwhp 2500 pound lotus killer. If they mess it up well the FD will just continue to compete in autocrosses and on road courses, have a greater chance of becoming a collector and give us more to talk about