synergy7

iTrader: (20)

Gordon what was Cmonakars 20b going to put out?

I will shear my opinion on the subject. I to have driven several fast cars as a mater a fact I just took 2008 GTR @ 150+ less than a week ago(it was not slowing down not enough road). That car is the “stealth bomer” of ugly but Oh Yeah it's FAST. If you guys can’t see the need for more power come to S. Florida. We have plenty of BIG $$$ exotics, 2jz Supras (putting out 1200hp) that will burst your 500 hp bubble in a blink of an eye. Every beat-up 240sx has some mangled engine swap (1jz, sr20, RB…) you can’t sleep on anything. Do you need power like this Hell NO, no one does but you will have to get used to losing a lot. Hell even the manufactures stepped up the game. Have you seen what the performance models on factory new cars the #’s they are putting down? I think the unwritten bench mark has been moved up to at least 500 hp or don’t come at all; is it at the wheels no but stock vs modified they are on your tail (STOCK). I am not sure about you but I am not looking to get smoked by grandma in a Volvo who does not know she’s beating me because the race is in my head.

Now to the 20b Build. Exotic parts are not required to make power it’s the sum of all parts that counts. I don’t think 1200 hp is realistic for the street, but to each his own. You need a plan its all about the preparation think NASA. Ask your self a lot of questions. When I build my 20b (which I do have) I plan on getting 700 reliable hp, yes street driven. Nothing exotic just 9.7 high compression rotors, balance job and concentrate on the tuning. High compression because I am street driven, I want the motor to be “more” responsive out of boost which is where I am 97% of the time. I know for a lot of you this is a topic of debate but there is more than one way to skin a cat. So for now I am looking into high compression LOW boost 15-17 lbs.

hwnd

iTrader: (4)

You'll need to run very high octane for the boosted 9.7:1 rotors. If low boost is 17psi and high boost is 30psi on those rotors.. less margin of error tuning and the higher octane you'll need (daily driving C16 will eat you alive).

hwnd

iTrader: (4)

Carlisi' car as it sits doesn't make massive numbers, all it's lacking is finer tuning of the cal.
We ended up using the 2nd Ignition map for split ignition but his calibration is *very* safe and for a good reason too. I think he was at the point of working 14psi fueling and from the logs I've seen he was surely getting to those bigger numbers.

synergy7

iTrader: (20)

Dont get me wrong octane counts but I think if you get the timing right you can run 93.

If you concentrating on efficiency the power will come, 9.7 are more efficient. I AM NOT CALLING ANYONE OUT, however I think we all saw Chrisped V8killa video which is a very impressive 2 rotor when you hear the numbers, but when I look at the dyno it looked very flat until 6500 rpm where the boost comes on like a cannon. TO ME that is not efficient. I know it had to do with turbo choice and tuning but its the best example I have.

I think that high compression rotors on low boost will give the best all around performance “I” am looking for. Off the boost the car will be stronger. Depending on the turbo boost should come in early (and again be stronger). On the boost the engine should run stronger pound for pound @ 15-17lbs range.

Like everything else now I will let you know when the economy pics up.

hwnd

iTrader: (4)

I'm using S5 NA rotors in my 3rotor.. You may have different findings than I did.

It's more than static compression (read: dynamic compression).. and depending on port timing etc you could actually have lower [dynamic] compression, etc but you probably know all that stuff already.

vincentrx7

iTrader: (2)

I have talked to several people that have built 500hp 13b's that said they would have come out cheaper going stright to a 20b. That is one reason I did a 20b. I wanted 500+hp but still have a car you can carry on a conversation in and not have your eyes watering at red lights from the unburnt fuel with a radical port job and tuning. I made 470whp at 10psi and 560 at 15psi. Nothing to really brag about but the car is pretty tame. The power delivery is smooth enough that I normally get traction at the higher boost in 2nd gear. I'm hoping my engine will last a long time at these low boost levels....I'm more concerned about the reliability of the drivetrain than the engine.

Chaotic_FC

well anyways guys, i'm pretty sure that this guy is more interested in having an extreme amount of HP. so why are we talking about how you dont need it? it sounds like he has his mind made up with a parts list like that... Besides, our cars do have ajustable hp due to them being turbocharged.

synergy7

iTrader: (20)

I am not the GURU never claimed to be, however I have driven High comp 9.7 turbo (FD) powerd cars and its like night and day. Like I said there is more than one way to skin a cat.

MB AMG uses low compression big displacement supercharged engines. BMW M series uses small displacement high compression high reving engines. They both make power but the go about it differently.

synergy7

iTrader: (20)

Disclaimer ***this post is not to be taken too seriously***

I hope this is close enough to the original topic to not be a thread jack….

Why is it…

… that Supras upgrade like Swiss watches? If 10 Supra guys buy 10 identical turbo kits you get ten 700hp Supras.

… if 10 Rotary guys buy 10 identical turbo kits you get 5 blown engines and 5 mixed hp out puts (5 blown at least). What is going on?

(This is literally and figuratively)

Is this the formula?

One guy makes huge power with his set up making him the new "GURU", so the Rx7 cattle flock to the same set-up and finger the engines until they blow. The entire time thinking they will get the same result if not better because they are the self professed gurus. Or that the one extra magic exotic part is going to be the difference in huge amounts of power.

In the early to mid 90’s many of us had the excuse of being the first to try the new piggy backs systems & turbo setups and oh yeah no Google (information with out trial). Those days are long gone but: 1. everyone is getting mixed results 2. Rotaries are still blowing up. What is it?

diabolical1

iTrader: (3)

i'm not sure i like the overall tone of your question, but i'll beat that horse again on another day. i suspect two things at work in your question/example.

1. JZA80 Supras were pretty much built for those numbers and detuned to the stock levels, but most of the ability to handle 500 HP is already in place. so it's relatively no-big-deal to extract it. doesn't take genius, just a little money.

2. of your 10 rotary guys, the 5 that blew up probably weren't using someone that knows what it takes to make a 500 HP rotary. others probably skimped in other areas. i mean you mentioned 10 turbo kits, but you didn't mention the port configurations of all 10 engines, what year engines, dowelling/studding, etc. - so you can still have 10 different engine setups with the same turbo kit. finally, much of it can probably be chalked up to the way the rotary makes power which will dictate the way it needs to be tuned (longer combustion chamber, heat and heat transfer, etc.)

hwnd

iTrader: (4)

You're mistaken. a change in the static ratio (1.5 in this case) is almost not enough to be felt by the seat of your pants. a whole host of other things come into play here, a lot. port timing is a major deal.

if you built two engines 100% stock using one set of s6 rotors and one set of s5 na.. you'd see a small increase hp/tq. If you still think those two fd's were magical, i implore you to talk with Racing Beat who has done this. Its no "night/day" difference... hell its only a change of 1.5! how could it be? ...years later, some poor kiddie will stop by this thread reading that you say night/day difference when using those rotors.. not true.

mcfly

if you ever went through with this i have a new gt4508r i can sell you

synergy7

iTrader: (20)

Agreed on paper it may not seem like much no one component does, However I have to disagree (no magic here) just personal experiences with 9.0 vs 9.7. I have already stated that it is a combined affect when building a cohesive system.

Agreed there are many other factors that go into making power (obviously). I cannot speak for you or Racing Beat. I can only speak for my own experience (night & day).

Ask your self: If you take turbocharging out of the equation which set of rotors would you want in your engine, and why? Remember I also stated that the car would not be on boost 97% of the time (real world).

In my previous post I tried to imply that given ten identical rotaries and ten identical upgrades there would be 10 very different results (blown motors aside). The truth is we do not live in a vacuum and there are so many factors into why I say night and day and you say not even.

BTW how long ago did Racing Beat do their testing? Were the motors carb, efi, ported, stock, distributor, ems vs stock ecu with piggy backs, ect?

I respect your opinion, but for now we can agree to disagree.

hwnd

iTrader: (4)

You can't compare two cars at all. "by the seat of my pants" isnt proof that one car-A is better than car-B. you know that.

I tuned a GT42r on a 1.09 hotside then switch to a .68 custom hotside. the owner of the car honestly swears its a whole new car, spools quicker (runs out faster too).. even ran a custom Alpha-N .vs Load/Map setup on the ECU, a hybrid of hybrids.

I'll bet you $100 he's going to recommend that GT42r to all his friends now. "such a night/day difference" while most of that success is due to this hotside, it's also due to a larger part being the hybrid calibration.

i think the point i'm trying to make is is car feels much, much more alive than anything he's been in. while he doesnt have all the details, he'll still recommend the turbo. make sense?

one car, two engines... fine i could maybe see your point but you're in two cars different engines and probably ecu's.. all that stuff makes a huge difference in the car.

if you still debate that high compression rotors are *the way* and make *huge differences in power gains* then I take it you knew both cars inside and out, tuning, etc.. I would then assume the weight, turbo, engines are all very identical 'cept the static compression... both engines had port opening/closing times based on a few paramters, etc..

...well hell, i still wouldn't believe a night / day (huge power gain) in using those S5 n/a rotors.
if that were the case, everyone would have jumped on the wagon long time ago. this surely isn't a 20B vs. 13B difference here... its just slightly more compression.

...btw, if its a big power gain, care to explain why a big portion of known drag racers use the lowest compression rotors? Jim was known for using 7.5 down to 7.2 on the drag cars.. carb'ed or EFI.. ..then again, he was probably still n00b-state back in those days.

synergy7

iTrader: (20)

...well hell, i still wouldn't believe a night / day (huge power gain) in using those S5 n/a rotors.
if that were the case, everyone would have jumped on the wagon long time ago. this surely isn't a 20B vs. 13B difference here... its just slightly more compression.

...btw, if its a big power gain, care to explain why a big portion of known drag racers use the lowest compression rotors? Jim was known for using 7.5 down to 7.2 on the drag cars.. carb'ed or EFI.. ..then again, he was probably still n00b-state back in those days.[/quote]

1st I never said hi compression was the end all in power gains just one piece in the puzzle

A lot of people did jump on the high compression bandwagon and a lot of them blew up (for whatever reason). Now there are somany nay sayers that most guys are scared to give it a shot. I believe that the knowledge and technology has advanced enough to handle the demands of a hi comp engine.

Drag racers use low compression to run high boost to make power. I specifically said hi comp low boost (or exactly opposite). They use low compression because they believe it gives them a higher margin of error to abuse the drive train harder. They putting the drive train to way more (RAW) abuse in one run than I plan on doing in the life of the car /engine.
Agin I make no claims to be the "Guru" I can I only speak for what I have seen for myself.

I will restate my question: "Turbocharging out of the equation what rotors would you use and why?"

Why did mazda go from 8.7 to 9.0 in the TIIs? Why did they move up the compression in the NA cars? (it works and yes I know thats not all they did).

Our engines are a fixed size we cannot not hone out the block to make it any bigger we can do a handful of things I choose turbo hi compression. I think it makes a significant difference.

But again I respect your opinion on the subject.

classicauto

iTrader: (3)

In my current build, I'm using 8.5:1 (S4 TII) rotors. Used S5 TII's in the past. Just found a good deal on these.

Like you say, its not all they changed. The largest increase in power (N/A) was due to the dynamic effect intake. Can't even begin to compare S4 and S5 TII. One ran higher boost, different manifolds, way too many variables there. But I'd bet that fuel consumption had alot to do with it.

Personally, I've driven a pretty wide range of these cars. Bone stock, S4 N/A vs bone stock S5 N/A has virtually no difference at all (with regards to the topic at hand) . There's slightly broader power in the S5 that you can basically only find on a dyno.

Also, given the nature of dynamic compression, a couple thou difference on a sideseal may negate changing over to rotors to higher compression entirely (aside from the weight difference)

I respect your opinion but a night and day difference is pretty outlandish for that change IMO. A night and day difference is stock suspension vs. coilovers. Or walmart tires vs. Hoosier R6's. Not a static 1.5 bump in compression.

Even look at stock HP outputs for all of them. Very very close despite all the changes.

hwnd

iTrader: (4)

well said

PDViper77

iTrader: (9)

Or you can do what I am doing. Two complete and seperate fuel systems. One using 93 octane gas and the other using methanol.

gusfd3s

1300hp? that engine was sold over a year ago and never produced any numbers near 1300hp.