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-   -   20B's performance margin diminished due to AI (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/20bs-performance-margin-diminished-due-ai-729139/)

kwerks 02-12-08 06:23 AM

i think this thread took the wrong turn from its original topic and point

ptrhahn 02-12-08 08:22 AM

Gordon,
When are we going to see/hear details on your build? You going to bring it out for a MazdaDrivers (formerly MADS) event this year?

Herblenny 02-12-08 08:47 AM

I agree with Gordon...

I think when FD goes above 450HP it becomes less and less streetable. Sure it sounds good since norm of this forum is MORE POWER means better.. But I'm sure less than 10% of the people on this forum knows how to drive 450+HP FD.. Most just don't need it.

I think someone brought up weight.. Hmm.. I also agree that NA 20B would be hell of a lot lighter than stock 13b-rew with all the junk on it. Sure the dry weight might be 30-40lbs heavier and with the liquid inside maybe close to 50-60 more.. but weight shouldnt be an issue unless you are building a track car....

Anyhow, Gordon, I can't wait to see that car at the DGRR..

zinx 02-12-08 08:50 AM

The power level is only part of the equation for traction, people always overlook suspension. I make 512 to the wheels and i will never break traction just rolling into the throttle on 255/40-17s. I have to shock them to break loose.

Howard, i usually agree with you, but not in this case. The only two things a 13B have over the 20B is gas mileage and price.

If you are traction limited then you need to focus your efforts in other places. Rear end, suspension, tires, ECU (Traction control, boost by gear), and other stuff.

zinx 02-12-08 08:53 AM


Originally Posted by herblenny (Post 7857006)
I think when FD goes above 450HP it becomes less and less streetable. Sure it sounds good since norm of this forum is MORE POWER means better.. But I'm sure less than 10% of the people on this forum knows how to drive 450+HP FD.. Most just don't need it.

I need more! A lot more! Who is going to take on those 1k HP Supra's and turbo'ed LS1s swapped 7s? I think the street power limit for an FD is somewhere around 700-750 rwhp, but there is always more you can do for straight line performance, but thats when you have to sacrifice turning ability.

bencb44 02-12-08 10:41 AM

How much reliability would AI help with? I know, of course that you're not gonna get a 600rwhp 2 rotor with 20 psi of boost to last for, say, 100k miles, but does anyone have any info on how long a well built engine like that might last?

These are just numbers I'm pulling out of my butt. My car's nowhere near that

Kento 02-12-08 04:18 PM


Originally Posted by gmonsen (Post 7856681)
1.3 and kento. Hi. Don't know you guys and hope this is helpful in clarifying what I was saying.

First, when I said I believe NA 20b's can easily make 400 whp and much more and be tractable and refined, it was because I have been building one. There are street cars posting 340+ in the 20b forum and race motors I know of making 450+. I saw a 13b NA do 265 the other day on carburators. I will have my motor running by the end of the month and believe it should make 375+ whp and yet be quite refined. We are starting a second motor that will make 450-500 whp and yet, hopefully be tractable and fairly refined.

Second, while its true that there's a third rotor with an NA 20b, you lose as much or more in weight and much more in cost by losing the intercooler, turbos, etc. There is no difference in weight and too little to be relevant in cost. However, the point of the 20b would still be that it puts out more power and more reliably and has a sound that is compelling to anyone who loves cars. And, with the 20b no one would complain about the motors' detonating and needing rebuilds.

I'm not really knowledgeable enough on the emissions side of things to comment, but the emissions need to be considered. Typical of me not to think of it!

Gordon

I don't doubt that you and others are able to build a 20B that can be powerful, tractable and refined. My point was that it's easy to look in hindsight from outside the constraints of corporate financial and marketing concerns that enthusiastic engineers must work under when bringing a car from concept to production reality, especially back then when Mazda was already on shaky ground financially. It's easy to say "using this would've been better, cheaper, maybe lighter", but material procurement decisions in a major manufacturer are rarely done without numerous other factors elbowing their way into the equation. The same could be said for the actual engineering aspects as well.

Sorry, this is veering off the intended direction of the topic. Back to your regularly scheduled programming...:)

ErnieT 02-12-08 04:22 PM


Originally Posted by zinx (Post 7857023)
I need more! A lot more! Who is going to take on those 1k HP Supra's and turbo'ed LS1s swapped 7s? I think the street power limit for an FD is somewhere around 700-750 rwhp, but there is always more you can do for straight line performance, but thats when you have to sacrifice turning ability.

As nice as it sounds, 750rwhp in a FD in NOT streetable. Not even close. You'll be dead in a ditch before you can blink. Im at my wits end running 20lbs of boost on the street (585rwhp). Just running 20psi, let alone 32psi, my tires lite up in 3rd gear! For the street, a 20B would be the ultimate ride. For the track, the 13B wins.

Copeland 02-12-08 11:05 PM

What kind of AI/WI injection kits are you all running? I am interested in how long a "tank" of it lasts. How many miles have you been running your AI/WI setup? Does your car have to be tuned for AI/WI or can you simply strap it on (reliability) and go? Obviously if you want the extra perks/power of the extra reliability you're going to have to get your car tuned for the AI/WI.

Herblenny 02-13-08 08:15 AM

My understanding of AI/WI is that its bandaid for those with shitty tune and aid for those who make shit load of power.

RX-Heven 02-13-08 10:34 AM


Originally Posted by howard coleman (Post 7850997)
and of course you can AI a 20B and make 800-900. please let me know what it is going to do for you beside totally frying your tires.

Race Logic traction control + 345's :D

Originally Posted by howard coleman (Post 7850997)
it is also possible to build a 20b FD right. it is also possible to totally screw up the front geometry.

Only if you move the rack and there are options that eliminate the need to do that now, not that us lowly FC guys ever had to worry about that in the first place.

ErnieT 02-13-08 10:41 AM


Originally Posted by herblenny (Post 7861431)
My understanding of AI/WI is that its bandaid for those with shitty tune and aid for those who make shit load of power.

Not at all. AI has so many benifits.
1. The water acts as a displacment adder because it doesn't burn so you make more power.
2. The cooling properties in water and meth are fantastic at reducing your intake charge temps so you can run alot more boost withou detonation, ie..more power
3. The water inj. also steam cleans the rotary and totally eliminates carbon build up as well as keeping the apex seals lubricated, preventing warping.
No bandaid, just added reliability and power. Something we can all use!:icon_tup:

zinx 02-13-08 11:04 AM


Originally Posted by ErnieT (Post 7858796)
As nice as it sounds, 750rwhp in a FD in NOT streetable. Not even close. You'll be dead in a ditch before you can blink. Im at my wits end running 20lbs of boost on the street (585rwhp). Just running 20psi, let alone 32psi, my tires lite up in 3rd gear! For the street, a 20B would be the ultimate ride. For the track, the 13B wins.


I don't have a 750 rwhp FD, so i've got to take your word for it, but i'm definitely craving more power in mine at 512.

What is your rear end setup like? What tires and size?

If those damn supras are out there making highway pulls with 11-1200 HP, I think we can make 700-750 work somehow.

Herblenny 02-13-08 11:43 AM


Originally Posted by ErnieT (Post 7861782)
Not at all. AI has so many benifits.
1. The water acts as a displacment adder because it doesn't burn so you make more power.
2. The cooling properties in water and meth are fantastic at reducing your intake charge temps so you can run alot more boost withou detonation, ie..more power
3. The water inj. also steam cleans the rotary and totally eliminates carbon build up as well as keeping the apex seals lubricated, preventing warping.
No bandaid, just added reliability and power. Something we can all use!:icon_tup:

Ernie,

Don't get me wrong.. I do understand the list you've provided..

My point is that most people on this forum don't need it.. But for someone who's trying to maximize HP, reduce detonation, and pushing the engine to the limit, like yourself, yes, it would be useful. But most people on here just don't have the knowledge to take full advantage of the AI/WI system... I mean would you recommend people putting AI/WI system on stock set up and turn up the boost?? Maybe...

But I just think too many people on here lack the knowledge of tuning and use the WI just because what they have read and misinformed.. I mean, Ive seen some people use tap water, no filter, no tune, nothing.. In that kind of case is when I say its used as bandaid.

iceman4357 02-13-08 11:49 AM


Originally Posted by zinx (Post 7861872)
I don't have a 750 rwhp FD, so i've got to take your word for it, but i'm definitely craving more power in mine at 512.

What is your rear end setup like? What tires and size?

If those damn supras are out there making highway pulls with 11-1200 HP, I think we can make 700-750 work somehow.


WORD!! I made my 490rwp and have been craving for more. I had 255's and spun all over, I addressed this by getting new wheels and drag radials. I now dont spin in any gear at any kind of punch. Now that the motor is down, i want to go for 600+rwp for the street. Around here, people have low 10 to 9 sec cars that they bring out on the street. Im just trying to keep up with the curve.

I also have AI, but i am going to run water instead of alky this next rebuild. The AI systems do have a clogged nozzle detector and you can install a low fluid warning light. I would opt for clogged, I refill my tank every time i got out.

XSTransAm 02-13-08 12:09 PM

I understand this argument, but for daily driving the 13brew lacks low end torque like nothing else. besides whos happy with just 500hp anymore?

My next build is def going to be a 20b unless i go the elise route...

FDWarrior 02-13-08 12:43 PM

I would much rather have a 20b for road racing. The low end, and rpm's a 20b can provide is perfect for a tight road course. I would say an N/A 3 rotor is a much better set-up for road racing, If money is no object. I do know that to do a 20b right takes alot of cash and time. I will agree a 13brew with ai is cheeper, making it more practical for the average joe.

FDWarrior 02-13-08 12:45 PM


Originally Posted by ErnieT (Post 7858796)
As nice as it sounds, 750rwhp in a FD in NOT streetable. Not even close. You'll be dead in a ditch before you can blink. Im at my wits end running 20lbs of boost on the street (585rwhp). Just running 20psi, let alone 32psi, my tires lite up in 3rd gear! For the street, a 20B would be the ultimate ride. For the track, the 13B wins.

For the dragstrip you mean

peachykeenwight 02-13-08 01:11 PM


Originally Posted by ErnieT (Post 7861782)
Not at all. AI has so many benifits.
1. The water acts as a displacment adder because it doesn't burn so you make more power.
2. The cooling properties in water and meth are fantastic at reducing your intake charge temps so you can run alot more boost withou detonation, ie..more power
3. The water inj. also steam cleans the rotary and totally eliminates carbon build up as well as keeping the apex seals lubricated, preventing warping.
No bandaid, just added reliability and power. Something we can all use!:icon_tup:

Don't forget lower EGTs!

Herblenny: You're right, I have seen many hackjob auxiliary injection systems in many different types of cars around here.. even then it provides SOME increase in reliability and performance. But, when done right, it really is killer. It is a cure-all for turbocharged cars. More boost, less detonation? It's brilliant! If more power is your goal, and you don't want a bigger turbo that will make the car less and less streetable, it really is a god-send. The other cool thing about it is that you don't have to back off your timing as you add compressed air. It is essentially like turning your 91 or 93 octane gas into something similar to C16 at a fraction of the price. The point I'm trying to make is that everyone could theoretically benefit from auxiliary injection, even on a bone-stock 13BT or 13BREW.

Cool thread, Howard. And a valid point. But the 20B still has [most of] our 13Bs beat in terms of torque and a more useable powerband. Plus, it usually sounds cooler too. :P

2FAST7S 02-13-08 01:26 PM

I went with a somewhat big turbo with the idea of making 400+ on pump and yet leaving some room to turn up the boost and make more hp. On that note we all know the limits pump gas exercises on us. So its either race gas or AI, and I'm leaning towards AI. Simply because of availability! You can fill up on race gas in a few selected spots easy enough...then what drive on it normally and use it all up? by the time you need it, its gone!!! where as AI is a matter of topping off the tank and youre good to go. not used all the time and it has other properties race gas does not.
I'll see once I tune on turbo alone where i end up and decide then if 400+ is enough. I've been going into the AI section and reading up on this, even if dont end up with it, its still interesting!

ErnieT 02-13-08 05:03 PM


Originally Posted by zinx (Post 7861872)
I don't have a 750 rwhp FD, so i've got to take your word for it, but i'm definitely craving more power in mine at 512.

What is your rear end setup like? What tires and size?

If those damn supras are out there making highway pulls with 11-1200 HP, I think we can make 700-750 work somehow.

I suppose Im a puss, cause I just don't have the balls to open it up 4th and 5th gear highway pulls, lol. Probably would have done it 10years, 2 kids, and a business ago, but not now. :coolkid01
As for my rear, as of now its a kazz, carbon driveshaft, toe links, trailing arms, solid diff mounts, and soon...custom one piece axles setup with hubs from the driveshaft shop.


Originally Posted by herblenny (Post 7862053)
Ernie,

Don't get me wrong.. I do understand the list you've provided..

My point is that most people on this forum don't need it.. But for someone who's trying to maximize HP, reduce detonation, and pushing the engine to the limit, like yourself, yes, it would be useful. But most people on here just don't have the knowledge to take full advantage of the AI/WI system... I mean would you recommend people putting AI/WI system on stock set up and turn up the boost?? Maybe...

But I just think too many people on here lack the knowledge of tuning and use the WI just because what they have read and misinformed.. I mean, Ive seen some people use tap water, no filter, no tune, nothing.. In that kind of case is when I say its used as bandaid.

Herblenny,
I think your still missing the point. With AI pump gas is no longer an enemy of a a rotary. We can run as much as 28psi on pump gas with AI. Its way cheaper than running C116 all the time and a single turbo (any single) running 20+lbs of boost on the road will whip most anything out there with only a few exceptions.

Herblenny 02-13-08 05:36 PM

..

Nevermind.. Ernie, I was never in disagreement.

MAXX65 02-13-08 05:50 PM

I just stumbled on this thread and read the entire thing....

I have never heard of AI before and after reading this it sounds like it should be the answer for everyone in every boat. It seems to me that AI is under the category of reliable mods and that people like me who want to stay with twins can still reach 350-400 reliably, while allowing those with death wishes to produce 600+.

So what’s the catch?

ErnieT 02-13-08 06:09 PM


Originally Posted by herblenny (Post 7863709)
..

Nevermind.. Ernie, I was never in disagreement.

Its all good bro. Not everyone shares the same point of view..:)


Originally Posted by MAXX65 (Post 7863765)
I just stumbled on this thread and read the entire thing....

I have never heard of AI before and after reading this it sounds like it should be the answer for everyone in every boat. It seems to me that AI is under the category of reliable mods and that people like me who want to stay with twins can still reach 350-400 reliably, while allowing those with death wishes to produce 600+.

So what’s the catch?

No catch!:icon_tup:

zinx 02-13-08 06:14 PM


Originally Posted by ErnieT (Post 7863575)
I suppose Im a puss, cause I just don't have the balls to open it up 4th and 5th gear highway pulls, lol. Probably would have done it 10years, 2 kids, and a business ago, but not now. :coolkid01
As for my rear, as of now its a kazz, carbon driveshaft, toe links, trailing arms, solid diff mounts, and soon...custom one piece axles setup with hubs from the driveshaft shop.

The more power you make, the quicker the pulls are over. Its safer really. ;)


j/k j/k I understand. I'm trying to get away from doing anything on the street but its hard when someone needs to get beat.

Got any more info on those one piece axles from DSS? He was telling me they were developing them when i stripped a spline of his stage 5's.


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