jorx7

iTrader: (11)

well i finally got around to trying this setup with the apexi pfc,and banzi racing adaptor kit for s5. we kept the stock map sensor. rather than the 3bar map sensor. which would not settle with a n/a tune. his dyno shows a 25-30% less reading in hp. so after the final pulls it read 156. plus 25% comes to 195. but gona go with 190. im getting my t2-n/a motor built this winter by jpr in south jersey. so im thinking a solid 200 hp. maybe more. enzo took his time with the whole tune. if your in the nj/ny/pa. area def recomend him.

video of my car.



http://www.youtube.com/watch?v=GUAva25ZBfs

http://www.youtube.com/watch?v=xReKVE3JUoI

rotormind

On what port?

jorx7

iTrader: (11)

stock ports. though my friend told me it had a small smoothing out of the ports or very small port job when motor was built years ago. mods : throttle body mods,vdi open,port sleeves removed. msd ignition amplifer,aluminum intake pipe. full racing beat exhaust. solid motor,trans,diff,subframe mounts, light weight fly wheel. premix. on 93pump.

jorx7

iTrader: (11)

this is a link for any one who hasnt heard of him. great guy. i was recomended by rich also know on the forums as GoodfellaFD3S. who had his road track fd tuned by enzo.

https://www.rx7club.com/rotary-drag-racing-167/congrats-enzo-917520/

widebodyseven

iTrader: (17)

So this is a T2 engine running na?

MOBEONER

iTrader: (18)

Why wont you add a stock T2 turbo? i am sure you will get much more HP. You do have a power FC!

jorx7

iTrader: (11)

the motor in the car is a s5 n/a motor. i am having a motor built with all t2 parts except using my s5 n/a rotors. this winter. big street port ,exhaust port. with that motor i should be at 200 hp mark. so i hope. when banzai racing did a tune for a n/a car they had. they got between 175 to 180. dont know how modified it was but it worked. i dont see the car making to much more when i get the motor. enzo did 2 more pulls after the first high power run, and they were the same power.

jorx7

iTrader: (11)

cause i want all motor. my next car will be turbo. we all desire different things. and my money was streching to thin for turbo build .

Banzai-Racing

iTrader: (11)

Why does the dyno read 25-30% low?

Which map did you use? Is it our dyno tuned N/A base map? If you are using any turbo map, then half of it is unuseable as the car never sees positive pressure.

Our customer's car is stock port S5 6 port, with intake filter, full exhaust, MSD 6A and 550cc injectors. It is an ITS race car so it is very limited on the engine mods and can not have an aftermarket flywheel. It made 189rwhp on a Mustang dyno with 40 mile engine break in(during competition) on a fresh rebuild. We actually have the car in our shop right now, we will be retuning it in a few weeks now that it has seen multiple race events and has a couple hundred miles on it.

It is at the bottom of our dyno gallery http://www.banzai-racing.com/dyno_gallery.htm

jorx7

iTrader: (11)

hey banzai. no we didnt use your map. i told enzo about your car he re scaled the map so 1-20 was negative. and did a full tune through all rpm ranges etc. but we used the stock map sensor with the car. due to the 3bar being made for high boost. the stock map sensor worked out perfect since it was never made to read boost. enzo has a Mainline Dynolog Dynomometer. they are made in austalia. im not sure why it read lower %. but he knew what the % was. i also kept the 460cc n/a injectors in. so when my new motor goes in next year then well see what i can get.

fidelity101

iTrader: (11)

stock port 195hp? 156 seems more reasonable with I'm assuming the minor mods you have on it

EpitrochoidalPower!

Whenever a tuner says that their dyno reads low i get sceptical. It just sounds like they want to make to customer happy and the customer is always ready to believe that their power figures are higher. If the dyno said 190 hp and the tuner said, sorry my dyno reads too high its actually 160 people would probably not believe him lol . Ever thought maybe all the so called low-reading dynos are the right ones and the rest are reading too high? Is the 190 whp or is it corrected to flywheel hp? Because 190whp with your mods seems a tad high. Sorry not trying to offend just don't want other people getting unreasonable expectations.

rotarygod

iTrader: (1)

Here's my opinion on dyno readings. Actually this is a rant so don't get offended as it is aimed at the general public and not towards any one specific person.

Anytime someone says that a "dyno reads low", all I hear is "this dyno is completely worthless for anything other than tuning and it's numbers are irrelevant". That's the complete truth. If a dyno is calibrated, they can't read differently pure and simple. People just automatically tend to believe the higher dyno's as it makes them feel all warm and fuzzy inside and then make excuses when using others. Horsepower and torque never change regardless of what a machine says. The number given is either correct or it isn't. There is no other option. If a dyno isn't reading correctly, then it can only be used for reference only to aid in tuning to help achieve a good consistent powerband BUT the overall power numbers are completely irrelevant. Therefore, we either say this car makes exactly 156 rwhp peak or we don't know. There is no guess work and there is no adding 25% to it as that's just a way to lie about what the car actually does. Why can't other dyno's be reading 25% too high? Maybe it does make that but until a calibrated dyno shows it (and who really knows which ones are?), no one knows and guessing is nothing to brag about. Sorry to be so blunt but it's true and we see it too often which only leads to others making excuses about what their car should make. Save that for the Supra forum. I "think" my car makes 350 hp but I could be wrong. It "feels" fast for a stock n/a! This is basically saying the same thing. Don't guess. Get a real number.

While we're at it, I also don't like the excuse where people try to guess how much drivetrain loss they are getting and then add numbers back in. If you aren't on an engine dyno, you don't know and NEVER WILL know what the engine makes at the crank! On a chassis dyno the only number that should ever be looked at is what is actually printed out. If this leaves some questioning how they can compare their numbers to others, you can't. Get over it. Dyno's DO lie!!!!!!!!!!! They are not infallible. If they were perfect, they'd all read the exact same and no one's dyno would read "25%-30%" low! They would all read the same regardless of who made it or where it is. They don't.

What the hell. One more thing. EVERY turbocharged car should show a NONCORRECTED map for altitude. Correcting for temperature is fine. ONLY a supercharged or naturally aspirated car should show fully corrected maps on both altitude and temperature.

I think that covers most of my general dyno complaints. Almost everyone, with the rare exception of a few, don't know what they are doing with these machines of reference. That's all they are. For reference only to be used to aid in tuning. They are not machines which give absolutes.

2a+RoN

Couldn't agree more!

Liborek

Sort of... Ever wondered how is possible that similar weight cars like FD, or even heavier cars can trap same MPH with literally less flywheel power than what some single turbo RX-7s are supposedly pushing to the wheels according to dynojet readings?

calculon

iTrader: (29)

Looking for some education here. Can you please elaborate, or point me to an elaboration, on why this is so?

I understand, and agree with, why uncorrected (for altitude) numbers should be what are considered for turbocharged cars, but fail to see how they are different from supercharged cars. Maybe I don't understand why you're suggesting uncorrected numbers are what matter and just have my own reasoning.

Rob XX 7

iTrader: (8)

I dont know how much he has calibrated this new dyno, I had questioned another person who got their car tuned asking if he figured the dyno out yet because I wanted to get a number on another vehicle of mine.

He said they dynoed a car they knew had xxx power ( I think it was like 500-600hp or so ) and it read 25% less, so I wondered if 25% was across the board. Maybe a 300hp car it would be 40%, or even 15%?
who knows?

190hp for a stock motor is very high

t_g_farrell

iTrader: (1)

Well said RG!

rotarygod

iTrader: (1)

Atmostpheric correction numbers for na cars is due to the fact that the air gets thinner with altitude and hence power drops off. The correction is an attempt to extrapolate (guess) how much power was lost and then "correct" for it. For a supercharged car, power also falls off equally with altitude as the boost produced is relative to engine rpm only. If you lose 10% of your power on an n/a by going up a certain amount in altitude, the supercharged car will also lose 10% of it's power. It'll just be at a higher power level. Boost on the gauge on a supercharged engine will fall off with altitude as it really has no way of knowing what it produces.

A turbocharged car on the other hand is different. The amount of boost it makes is based on what the wastegate spring or boost controller tell it to make. As the air gets thinner with altitude, the turbo spins faster and pushes more air as it has to in order to get the same pressure reading. A spring doesn't know that the air is thinner and it will still require the same amount of pressure even in a vacuum which wouldn't be possible. A boost controller could actually mess things up a little bit as it may be searching for boost off of boost over ambient which would mean that although you get a certain amount of pressure greater than ambient, ambient itself may still be lower than it would be at sea level. Confused yet? I'm sure there was something about that which may be unclear or confusing and I probably left some detail out.

Since a turbo system will generally try to compensate for altitude (to a point), it is most accurate to not use atmospheric correction on a dyno as it will typically overinflate the numbers to above what the engine actually makes. It may look impressive on paper but that's all it is, a number on paper. Reality says otherwise. Temperature corrections are fine for any engine. Saying that, you are probably wondering how we can truly get a fair comparison for different engines at different altitudes and locations. Again, we really can't. We can only get generalizations. There is only 1 truly accurate way to compare 2 cars and that is to compare that at the same time and at the same place. An n/a dyno that reads 200 rwhp may only read 185 rhwp somewhere else and there is absolutely no way to be sure which one is correct. Another possibility is that both are correct and that the car only made that much power on those particular days and the final possibilty is that neither is correct.

If you see a turbocharged dyno plot and it used altitude compensation, I don't care what excuse the owner or dyno operator gives you, just be aware that the number you see is overly inflated on the high side and the engine doesn't make that much power. Their opinion or anger against you for pointing it out doesn't change that.

At some point the disbelievers or haters are going to chime in so this could get quite interesting.

calculon

iTrader: (29)

I thought that that's what you were attributing your statement to, and understand (I think) everything that you're saying, except that superchargers don't produce the same boost at a given RPM at different altitudes; they produce the same pressure ratio. Hence, it is my understanding that they should be lumped with turbocharged cars into a category of forced induction, which can be contrasted with naturally aspirated.

Completely hypothetical, and mostly arbitrary example:

At my elevation, ~6,000-ft, my hypothetical Rotrex spinning at ~90K RPM, corresponding to an engine speed of ~7K RPM, is blowing air at a PR of ~2; which means about ~24.4psia. When I take a spin down to my friend in San Diego, I wrap my same engine up to the same ~7K, and therefore my Rotrex to the same ~90K, but now my engine is being fed air that feels like ~29.4psia. Supposing my ECU were smart and tuned well, I'd be pushing a good bit more power than a linear correlation (e.g. a constant like a dyno correction factor) would suppose because it'd be corresponding to an engine eating ~24.4psia air at ~7K RPM, where it's actually eating ~29.4psia air.

Am I misunderstanding or misrepresenting something? Truly just seeking a better understanding.

Thank you kindly.
ryan

jorx7

iTrader: (11)

i do agree with rotarygod on what he said. and though i dont want to spend more money before my motor build, im probablly going to take her to the shop i know by me. and do a power run to test it out. also plan on doing some runs against my friends t2. but the fact that i got the same numbers as banzai racing me makes me question if my power is correct ?

Banzai-Racing

iTrader: (11)

But you did not get the same numbers, you got 156hp with a "bonus" 25-30% just thrown on. We got a documented 189rwhp.

Take your car to another dyno and see what it puts down.

Rob XX 7

iTrader: (8)

you can go locally and just get a power pull, usually charge $50-$75

rotarygod

iTrader: (1)

Pressure ratio is correct. A turbo is going to reference boost from one of 2 things if so equippped. A wastegate spring will open with a certain amount of force on it and we translate this into a certain amount of air pressure. Pressure ratio having nothing to do with it. The thinner the air gets, the higher the pressure ratio needs to be to get the equivalent force to push the spring open and at some point the pressure ratio required will be impossible to hit. The other thing that may control boost is a boost controller which will try to maintain a certain psi above base as it does have a reference to outside pressure. Regardless of whether your outside pressure is 14.7 psi or 12.7 psi, the boost controller if set at 6 psi will try to aim for 6 psi above that base number. You can see that the PR is different for each.

Both of them will result in a different pressure ratio than what they'd get at sea level. The naturally aspirated or mechanically supercharged cars will always have the same pressure ratio regardless of altitude. That's what the dyno correction is for. It is basically equivalent pressure ratio correction and you can't compensate for something that isn't constant which is why you can't apply it to turbocharged cars and expect an accurate result. The turbo is already trying to compensate and correct itself.

calculon

iTrader: (29)

I have identified my malfunction. Much appreciated.