EJ257 vs EJ20G

[adrianvos]

Hi All,

Although not fully tuned and sorted yet, I thought some people may be interested in some dyno graphs showing my old liberty RS engine (MY96 heads with VF23) vs the new EJ257 (MY98 heads and VF34 with the VF23 exhaust housing). Of course the fuel system and ECU has changed also, but the exhaust, and intercooler are the same.

The graphs should explain why I am looking at changing turbos and intercoolers.

Here is the catch.... I have not got any ability to host the image, so can anyone else do that for me?

-- Adrian

[MY92]

http://tsukuba.orcon.net.nz/ej257.jpg

[Manaz]

So basically the engine is substantially better in every way (except maybe for fuel consumption, but something tells me that's not really an issue!).

More power, coming on harder and earlier. Boost seems about the same, but comes on earlier and is more stable (doesn't trail off quite as much).

I know that torque graphs aren't much good for showing absolute figures, but they're good at showing the differences between two setups - did you get torque graphed at all?

[adrianvos]

I have another graph with RPM instead of roadspeed for the 2.5L as I did not have the RPM input setup on the 2.0L dyno curve, so graphed it against kph which is the same for each.

Basically on the dyno the rpm is 39.3 * kph, so 100kph is 100*39.3= 3930RPM.

So 80kph is 3144RPM. As you can see, power has jumped from about 43kW to 87kW... about double the power at the wheels.

This engine is all about torque. It is very quick, but feels a bit flat above 4000rpm. I am probably going to change the turbo and intercooler to improve the top end. I doubt the bottom end would suffer that much.

I should also note that the 2.0L had about 320,000kms at the time of the run, and the compressor wheel was damaged on the turbo (two bent blades. I did put it on the dyno after converting to VF28, but despite the good compressor wheel, it made less power up top, and a bit more down low. The low air flow on the dyno seems to really kill my RS.... the 2.0L also ran 16psi through the range on the road, but dropped off up top on the dyno as you can see.

-- Adrian

[Manaz]

So, when are you running it up on the dyno next, with what changes, and how do I organise to be there? :)

I'm considering an EJ257 transplant with my MY02 RX, it would be interesting to see the engine in the flesh.

Cheers!

[Az]

i bet the torque curve is like a mountain, up up up, then down down down... the sign of too smaller turbo. i assume thats why the power flattens out after 100kph. with a larger turbo, power should be linear to about 6000rpm. should net more like 230kw ATW with the right turbo, and still have less lag than the 2L.

well done and congrats on the build..

I wish mine was on the road.

[Karupt]

Adrian,

From that image I can see, was the car dyno'd in 3rd gear or 4th ?

[adrianvos]

The only sign that is not stock looking at the engine is the EJ25 stamp on the block. It is nothing to look at as such.

I have graphed estimated flywheel torque from the dyno. It climbs rapidly to 440Nm at about 3800rpm. It then drops down linearly to about 280Nm at 6500rpm. It is certainly a case of the turbo/intercooler system being the limitting factor, but I am running standard internals, so I am not keen to push it too much further. I would be happy if I could get a FMIC and TD05 18 or 20G to push it up to about 200kW ATW. I will probably leave it as is for a while to think about this, and do the intercooler first to see how much difference this makes alone. I would be happy if I can get the curve to be similar shape to the old curve.... just much more everywhere... I am happy with the bottom end. below 4000rpm... just need it to push closer to 200 at 6000rpm.... as if really does feel quite flat at the moment in the top end.... same old story of change in power feel more impressive than the power itself!!!

I do all my runs in 4th. Most shootout mode runs are in 3rd... it would probably be about 165-170kW ATW in 3rd..... I would love to see an RS do 170kph in 3rd!! :)

-- Adrian

[EJ20TMAN]

The only sign that is not stock looking at the engine is the EJ25 stamp on the block. It is nothing to look at as such.

I have graphed estimated flywheel torque from the dyno. It climbs rapidly to 440Nm at about 3800rpm. It then drops down linearly to about 280Nm at 6500rpm. It is certainly a case of the turbo/intercooler system being the limitting factor, but I am running standard internals, so I am not keen to push it too much further. I would be happy if I could get a FMIC and TD05 18 or 20G to push it up to about 200kW ATW. I will probably leave it as is for a while to think about this, and do the intercooler first to see how much difference this makes alone. I would be happy if I can get the curve to be similar shape to the old curve.... just much more everywhere... I am happy with the bottom end. below 4000rpm... just need it to push closer to 200 at 6000rpm.... as if really does feel quite flat at the moment in the top end.... same old story of change in power feel more impressive than the power itself!!!
-- Adrian You should have no probs with alot more power, theres kits for the us sti thats quoted to make 420hp at the wheels on standard internals so 200+ kw atw shouldnt even be a ask of it

[MY92]

Don't forget the DynoJet's that a lot of yanks use have a different amount of drivetrain loss compared to the Dynamic Dyno's and Dynapacks.

[EJ20TMAN]

Well they reakon that its 500hp at the fly and 420hp atw's

[adrianvos]

Is there any links to these sites with kits.... what turbos are they using.... what intercoolers?

-- Adrian

[rony]

Does anybody else see whats wrong with that dyno graph???
I'm going to be a bit blunt here, there's no way you have an extra 40odd kw at 80kph! The runs start at different speeds, they are not comparable!
The start points of each run need to touch or at least crossover over somewhere. I see this all too often, the dyno operator has the ability to drag and drop a run anywhere on the graph with the dyno dynamics software, usually where it looks nice.
The only thing you can compare on that graph is max power because the start of the runs at least allmost line up horizontally.
Do you see what I'm getting at?
And 157kw for 2.5ltr is low, most decently modded 2ltrs are getting that, definitely change your turbo and/or cooler. I'd start with cooler.

[adrianvos]

Hey rony.... I was the dyno operator!!!!!!!

I did not fudge anything... if I was going to fudge it I would have made it read 200+ kw ATW!!... the first curve was my car back in April of this year when it was 2.0L when we first got the dyno. There was no point in starting the run at 2000rpm with that setup as it had no boost, and would only heat up the intercooler quicker to reduce the max power. The higher power run is monday night... when I was doing some tuning. Because she has real power not at 2000rpm, I start the runs earlier which would also contribute to the lower max power.

Why is that some people think they know everything about dynos when they have never used one!!!! Let me know when you have a few hundred hours experience of dyno use and tuning!! I have just come in for a drink break as I am tuning a B4 currently!!

And another thing... you can;t drag and drop the run anywhere.. you have very limitted flexibility in shootout mode... and if you read the rest of the thread you would realise 157kW is low.... it is being done with stock WAIC, and a smallish turbo. What is impressive is that it make 90% of the peak power at abour 3800rpm and holds it above 90% of peak power to redline.... that is atleast 140kW ATW from high 3s up!!

-- Adrian

[rony]

Adrian, I'm not having a personal dig at you, I didn't say that anything was fudged and I don't claim to know everything about dyno's, I just can't understand how 2 different dyno runs starting at 2 different speeds can be compared to/against each other. Could you explain it ?

[adrianvos]

I don't understand how the speed at which they start has any bearing??? Please explain to me how you think this can effect the power curve???

From my experience of operating a dyno, which is probably more than anyone on this forum, all I can say is that if you start a dyno run from a lower speed, there is a few effects:

* The turbo intercooler system has to work for a longer period as the run goes longer, so the power at the end of the run (near peak power) will be lower

* The turbo has more time to spool up, so you may get better bottom end power, but this effect is nullified by my next point........

When you do a dyno run, you get the car to the speed (or RPM) that you want to start the run at with the dyno free rolling with no load. You then flick a switch which tells the dyno to load the car at the current road speed. At this point the dyno will prevent the car going above this road speed no matter what you do with the throttle. You must then flick another switch to start the run which basically commands the dyno to start ramping the speed up and recording the power. Now you can sit in the state with the car loaded before the run as long as you like.... it is a compromise. I normally wait a few seconds in this state with the throttle fully open so that the turbo can get up to speed before the run, but this would no doubt cause the intercooler to start heating up before the run....

Anyway, my point is that if you hold the dyno loaded at WOT for a few seconds (as I do) before you start the ramp, this gives the turbo plenty of time to spool up to the maximum it can for the current engine speed. Therefore it does not matter what speed the run starts from as the turbo is always ready to go, but obviously the shorter the run lasts (higher speed you start), the less time the intercooler is loaded, and the lower the intake temps at max power, and the higher the peak power. If I want to get the highest peak power I can... I will start the run from 4-4500rpm.

Please explain to me how you think the speed at which the run starts effects the power curve.

I can tell you right now that my car does have that much extra power down low, and you can feel it to drive it also. The curve matchs my feeling driving it... it is much better down low, but the top end does not really feel much better than before.

-- Adrian

[EJ20TMAN]

Is there any links to these sites with kits.... what turbos are they using.... what intercoolers?

-- Adrian Here u go matey, http://www.xcceleration.com/5.htm I think there garret GT32's and big front mounts

[rony]

Adrian, I think you've lost track of what I'm trying to say, I didn't say anything about the power curves, I love the curves they look great, what i'm trying to get at is the comparison isn't very good.

If you wanted a true and accurate comparison between a EJ257 and EJ20G everything should stay the same, start speed, turbo, mods(you've changed at least 2 of these things).

At the moment I guess the above graph is fudged because you've loaded up the engines where they both like to work the best, the 2.0 looks like a bag of shit, where its probably not quite as bad as it looks out on the road say racing from a rolling start, especially if the 2 cars had the same peak output.

Your topic should have read "my old setup vs my new setup" or something like that because I don't think that graph compares engines very well considering lots of things outside/bolted to the engines have changed.

[adrianvos]

I agree with some of what you have to say, but I made it very clear that the following things have changed which would effect power:

* Heads
* Turbo
* Fuel management system

Also, there are some minor intake tweaks, but doubt they would make much difference at these power levels.

The reason for my post was that plenty of people are interested in how it is going. I did not try and say that it was a scientific test of a 2.0L vf 2.5L. If I had the time and money to change only the short motor, I may have done this. I was just trying to show the benefits of my old setup vs the new setup.

I can assure you that if I could put my old 2.0L in in 15 minutes and do a dyno run from 2000 rom, the curve would be near identical... I did it many times, but just picked the curve that was easiest to find.

In real terms, there is not that much different except the 2.5L. The exhaust, intercooler are the same, and the turbo is very similar.

I can tell you the 2.0L was as bad as it looked or I would not have swapped it.

-- Adrian

[Manaz]

To me, the end result is what matter.

ie what Adrian's old engine produced at it's best, and what his new engine produces, at it's best.

There's no point in running a turbo and IC that suit a 2L engine on a 2.5L - you're just choking the 2.5L engine that way, reducing it's ability to show what it can really do.

Turbos, intercoolers, heads, fuel pumps, they can ALL change. What's changed is irrelevant - it's the result that counts.

What the current set of graphs show is the progress that Adrian has made - I really look forward to seeing graphs showing further progress, and then a final "OK, the engine's all set up how I like it" graph.

I reckon that'll be awesome :)

[adrianvos]

To me this is a learning exercise... trying to do things slowly to work out what works, and I am sure others will benefit.

Things I have learned so far:

* Despite my previous belief, and what some others here cling to, I don't believe the standard WAIC is good for any more than 150kW ATW. It will do more, but it is past its efficient limit, and I believe that it would be compromising alot of power

* I thought that putting on a smallish turbo would compromise top end power, but give much better bottom end. In reality, it seems that bigger turbos still have very good bottom ends if setup right on a 2.5L. I would recommend in future going bigger than the VF series turbos on a 2.5L as otherwise the turbo will be the limit of power, and there will probably not be a huge bottom end benefit anyway.... I have seen dyno curves for 2.5L with much bigger turbos than me that come on boost earlier than me!!

I believe that with the right intercooler, I will probably do 180-190kW ATW with this turbo, but I doubt it will do any more. I know some claim over 200 with a VF34, but come and show me on on my dyno!!

-- Adrian