RETed

I got this from Paul Ko @ K2RD for this gem of data.
Dyno graph shows runs from the exact same motor with runs made on the same day.
One run was done with the stock ECU and the other with a Haltech E6X.

The motor was a very tired race S5 race motor with *S4 turbo rotors* - 8.5:1 compression ratio.
Exhaust is "3-inch".
Ports are stock.
This is why the numbers are kinda low.

What's more interesting is the difference between stock ECU versus stand-alone EMS.




-Ted

gsracer

I'd be more interested in seing that car tuned via a safc and then by the e6k. It's not exactly a fair comparison when one run is dipping into the mid 11's, while the other run is hugging 13:1 air fuel numbers.

drago86

Awesome ted,.. ive allways wondered,..

RETed

Sure, if you want to donate the time and resources, I'm all for it!


-Ted

Turblown

iTrader: (12)

Good info.

bingoboy

did something break, i don't see a dyno-graph

DocMazda

yup, the dyno graph would be great.

bingoboy

oo it shows up now. neato.

von

Wait so thats a 10rwp difference? Not only that that motor must be really tired. I made more then the e6k run while using the stock ecu. I think a couple guys are in the upper 178rwp range with the e6k without headers.

von

also when I did a before after with my s-afc I gained 8rwp with a high 13.8-14 a/f ratio. I think there is some tuning to be had with this e6k.

RETed

I think it's better as a percentage gain instead of absolute power gain.
If I remember the numbers, it's a 7% gain.
As mods go up, typically the percentage goes up also.
With a 7% gain, a motor making 160hp should be making at least 170hp.

Yes, the motor was described as "tired".
The rotor housings were described as barely usable.
The motor was build from a mix of parts they had laying around.
K2RD uses this race car more as a test bed for their products rather than shooting for wins, although I heard they just won their class for the season - NASA PS2, I think.

Keep in mind there is no porting allowed in this racing class, and I don't think the car was running any type of header - I think they were using the stock exhaust manifold still.

If we calculate 15% drivetrain loss, the motor is making 170 - 175hp range bhp at the flywheel.
Given the drop in CR to 8.5:1, that's not that bad - stock S4 = 146bhp, 9.4:1, stock S5 = 160bhp, 9.7:1.

Yes, this is not the most ideal testing conditions, but I haven't heard of anyone pulling off something like this before.
Keep in mind, the dyno runs were made on the same day.
The Haltech E6X was installed hours after the original baseline run with the stock ECU.
Yes, it would've been nice to have a properly tuned S-AFC to compare, but I'm not dropping the money or the resources to have this done.
I'd welcome anyone else to provide data if they have the time, money, and resources to do so.


-Ted

P.S. - the server drops pretty consistently during the night, but it should be okay during the day.
This would explain why the pic isn't showing at this time.

von

Ok well if this data you have is so rare then I mabey I can add that I did a before after with RB headers and got 13rwp. Ofcourse I had no emissions and custom short ram intake exc for the intake side wich is why it opened up so much with the headers. If you put on a straight pipe and rb headers im sure you can gain 20rwp with your setup considering you have no maf ?

RETed

Yes, gains should go up as more mods are done...up to a point.

I dunno if someone still has this GRM issue, but they did a 1G GSL-SE 13B 6-port with an Electromotive TECII, and they got the car to do mid 13's.
If the car wasn't lightened extensively, I think the HP range would've been around 200 - 220hp at the wheels to produce that kinda 1/4-mile times.
If we extrapolate back to a ported engine with full exhaust, most of these 13B 6-port NA's will do around 160 to 170hp at the wheels.
Best case 220 from 170 gives us a +30% boost in power.
I typically quote stand-alone EMS gains anywhere from 10% to 20%, which would easily fall into the above example "on average".
Although the K2RD graph gives us 7%, it's still not unreasonable in gains.


-Ted

Rex4Life

None the less this is a good indicator of how much "tuning" can improve an engines horsepower.

Thanks for posting up some good info Ted.

Scott

wozzoom

Thanks for the info Ted but I agree with gsracer... The stock ECU is running 12 AFR's while the Haltech is running high 13 AFR's. If you were to run the stock ECU with an S-AFC and tune it for similar AFR's (OR the Haltech tuned for 12's), would the difference be negligable? I'm sure it would be less then 7%.

My last dyno with a stock ECU and S-AFC, I picked up about 5% RWHP by tuning the AFR closer to 13.5-14. See attached.

RETed

So was your engine stock ports?
You did read my repeating comments that the engine was running 8.5:1 compression rotors, right?
You did read the engine was tired, right?

I don't think a stock port NA could hit 170 to the wheels?


-Ted

wozzoom

No, this my engine is not stock and has the high compression rotors but that's not the point...

I think the experiment you did with the stock ECU vs. Haltech is valid because you used the same engine and showed a considerable gain in performance. But what really gave you that gain? Was it the change in AFR's or something else tuned in the Haltech? Can you get that same gain on an NA with the stock ECU and a piggy back???

NZConvertible

Leaner mixtures, more aggresive ignition timing curves, removal of AFM. Also remember there are other more important aspects to an engine's performance besides peak power that a dyno can't show, like throttle response, driveabilty and overall "niceness" of the engine's performance that are all likely to improve.

No.

gsracer

While I think everyone would agree that a stand alone is better than the stock ecu in every single aspect, I think that dyno is misleading. The difference in power on a 13b when running mid 11 air/fuel ratios' vs 13:1 or higher ratios is a rather larger difference.

However I think the more actualy dyno's we are able to post on this forum, regardless of number, the better educated the average rx7 owner will be. I encourage anyone to post up any and all dyno's they may have of their cars; but I did think that an ignorant or new rx7 owner might believe that slapping on an e6k onto their n/a would instantly result in a net gain of 15 or 20rwhp.

NZConvertible

It's not misleading at all. A significant part of the reason for fitting programmable EFI is so you can change the mixtures for more power, and this is the proof that it works. It's a perfectly legitimate comparison.

Before you call others ignorant, you should remember that there are more important things than peak power. Look at the gain at 6500rpm; from 131rwhp to 145rwhp. That's 14hp or a 10% gain, which is quite a significant gain for minimal mechanical changes. Peak power is only a small part of the whole performance equation.

RETed

Um, ok...
I think you make a pretty good case you're not acknowledging the legitamacy of this data.

The point of the whole exercise is to show going from a stock ECU to almost any stand-alone EMS can do.
Remember, the runs were done within several hours of each other, so this minimizes any variables in terms of weather.
The fact that it's the same exact engine eliminates variances in engine VE due to porting and variances in production tolerances of the engines.
I didn't put the dyno graph up to brag how much power the engine is making.
In fact, a lot of you laughed at how low the peak HP numbers were.
That was not the point.
If I could've stuffed some kinda S-AFC in the middle of it, I would've...but this wasn't my test, and I had no control over it.

This was just an exercise of an NA engine going from stock ECU to a stand-alone EMS.
Nothing more; nothing less.
I do not know of many people who go from stock ECU to S-AFC to stand-alone EMS.
Most NA owners go from stock ECU to S-AFC and are satisfied at that.
I do know of people who go from stock ECU to stand-alone EMS.
I know people who are curious of what a stand-alone EMS can do (for their NA).

Like I said before, if you are willing to do a stock ECU versus S-AFC versus stand-alone EMS, I welcome such data.
I think we would all be grateful for such data.
I do not have the resources at this time to do this.
This dyno graph was dumped in my lap and was free.
I just wanted to share it with the rest of you guys.


-Ted

DaveB

Was that the GRM car that was painted red? If it was, it now resides down the road from me, and has a 12A in it. I have the origional 4 port engine that Pettit built for them that dynoed at over 200 RWP. It had a Haltec F3 fuel computer on it. One of these days I am going to rebuild it and put it in a play car.........

db

coldfire

iTrader: (1)

good post. it's always good to have some real world tests for this sort of thing, and it is seeming to bring out some good comments (pretty much all the posts thus far have been informative).

what i really want to support is NZ's point on the driveability characteristics that may change when you put in a standalone. many times race cars may not have the most impressive number figures, but i think they can tune really well for the feel and response of the car. sometimes that in itself will get you better lap times...

one thing i was just wondering, how much of factor does the wrong compression ratio play into the lack of performance from the stock ECU?
i mean, i currently have an S4 block with an S5 ECU and everything else, and i find that i run pretty rich and dump a lot of fuel between shifts or rapid RPM changes (read: flames). i attribute this to the 0.3 compression differnence slighty affecting the ECU's maps...
i would think that the 8.5 rotors would make an even larger difference. just a thought...

was this an S4 or S5 ECU?

also, one more question. with the lower compression rotors would you be able to run more aggressive AF ratios? i wouldn't think so, at least not so much as to gain horsepower.

gsracer

I might be able to do that, I'm currently on the e-manage and plan on going to a dyno soon; but I'm also looking to go with an e6k or lt8 as soon as I have the money. My posts weren't attacking the dyno or you for posting it, I just noticed the difference between a/f numbers and realized it wasn't going to be a perfect comparison. It does however show the potential a EMS has over the stock ecu.

NZConvertible

A small compression change would not cause those symptoms.