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Dyno test, 931 vs Honda typeR K20

 
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CÚdric  



Joined: 27 Aug 2004
Posts: 1752
Location: Sweden

PostPosted: Tue Dec 13, 2016 6:59 pm    Post subject: Dyno test, 931 vs Honda typeR K20 Reply with quote

Hi !

Just thought it would be fun to post a comparison i did yesterday. I guy at work has a stripped out Renault 5 with a k20 engine. The car is really fast and the noice levels are mad inside the car

We have been comparing some lap times (I still in lead on this point), acceleration logs(get humiliated here though:)) etc last days so i thought it would be interesting to see engine characteristics on the dyno.

This plot is a std Civic type R(borrowed some data) vs my 931, power is at the hubs, same type of dyno (Rototest) but different locations. My run is a 300rpm/s sweep, so looses a bit bottom end compared to static runs. His actual car is still to be dynoed, he has built a tuned manifold, high flow intake and made some recalibration of the cam switch, ignition and phasing, so probably a bit more than this stock car. well se further on !

Very different type of engines, but an interesting comparison. My future upgrades will probably even out the acceleration bit in the future, only time will tell





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morghen  



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PostPosted: Tue Dec 13, 2016 10:32 pm    Post subject: Reply with quote

Very interesting indeed.
Thanks for sharing.
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Raize  



Joined: 18 Sep 2013
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PostPosted: Tue Dec 13, 2016 11:22 pm    Post subject: Reply with quote

Is the 931 torque curve supposed to look like that?
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CÚdric  



Joined: 27 Aug 2004
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PostPosted: Tue Dec 13, 2016 11:42 pm    Post subject: Reply with quote

Raize wrote:
Is the 931 torque curve supposed to look like that?


More or less, my engine with this compressor seems to have more power at the higher end of the torque curve than a standard S2 when I overlay the curves. This is with my ROW DITC box, my swedish box was loosing a bit more torque after 4500rpm.

I had all the plots in here, but google seems to have changed image sharing links. http://www.924board.org/viewtopic.php?t=40495&sid=1562d6cd3306b377beaf215ddfa0ab51


I tried to get the oem curve from the manual in my plots, the curve fit is ok, but in the real curve the standard s2 falls of much sharper after max power.

Remember that the curves are at the hubs and reference is at engine. According to rototest database statistics (consisting of hundreds of new cars tested when new) a reasonable power train loss for a car like mine should be in the region of 10-11%, which nets around 185hp @ crank. seems reasonable if you look at the characteristics of the curve.

(I have larger 2664 compressor and s1 WG spring @ 0,7 bar, engine is otherwise s2)


Never run KN panel filter was also a lesson, much worse performance than std. I have had it on the shelf since i got i for free and it will stay there

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CÚdric  



Joined: 27 Aug 2004
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PostPosted: Wed Dec 14, 2016 5:55 pm    Post subject: Reply with quote

About the torque curve though, when you compare to the OEM curve for example you need to have in mind that it is static measurment. When I tried some static points from 3-6k rpms we got full torque at 3k rpm, but at 300rpm/s i weep didnt. Sweep speed is critical for a turbo car, hence impossible to compare different roller dyno sweeps if you cant control the sweep speed or run static. I ran 300rpm/s because after looking at track logs its a good number for reflecting 3-4gear acceleration. Which is where im mostly at on the track.
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Fasteddie313  



Joined: 29 Sep 2013
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PostPosted: Wed Dec 14, 2016 7:25 pm    Post subject: Re: Dyno test, 931 vs Honda typeR K20 Reply with quote

30+ year old car holding its own..
Think you could degree the cam a bit to move some of that torque up the RPM scale? You do actually use it up there..

CÚdric wrote:
My future upgrades will probably even out the acceleration bit in the future, only time will tell


A bit of fiddling around and he won't know what hit him, game over..
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CÚdric  



Joined: 27 Aug 2004
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PostPosted: Wed Dec 14, 2016 8:08 pm    Post subject: Re: Dyno test, 931 vs Honda typeR K20 Reply with quote

Fasteddie313 wrote:
30+ year old car holding its own..
Think you could degree the cam a bit to move some of that torque up the RPM scale? You do actually use it up there..

CÚdric wrote:
My future upgrades will probably even out the acceleration bit in the future, only time will tell


A bit of fiddling around and he won't know what hit him, game over..


My car is certainly running good for an almost stock engine.

That would make me loose speed probably, power curve is already quite peaky since power is rising all the way to red line. Looking at the power curve it would probably be better to rev to 6800, to spend more time at max power. At least with this specifcation. Normally turbo engines are quite flat at the top end, so you can rev past peak power to optimize shifting. But the 2664 is probably a bit to big for 180hp, would probably be good for another 20-40 hp safely. But it works much better than the originial 2660 when things get hot on track, with the original turbo the power got quite soft after a while.

If I look in the KKK software I can se that the Audi quattro (200hp), Nissan Fj20ET (205hp) , ferrarri 208GTS turbo (220hp) uses the same 2664 compressor housing, just for reference.

But im going for 2670 billet wheel anyway on the turbo im building


It will be really tought to beat him in a straight line, 935kg, super short gearing, 6spd and ca 210HP will be hard to beat. He will add LSD this winter aswell
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Mike9311  



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PostPosted: Thu Dec 15, 2016 12:50 am    Post subject: Reply with quote

Thanks for all this. Lots of interesting info to wake up to
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Carrera RSR  



Joined: 08 Jan 2010
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PostPosted: Thu Dec 15, 2016 5:59 am    Post subject: Re: Dyno test, 931 vs Honda typeR K20 Reply with quote

CÚdric wrote:
He will add LSD this winter aswell


And he's getting the power down cleanly without one currently?
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Fasteddie313  



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PostPosted: Thu Dec 15, 2016 6:50 am    Post subject: Reply with quote

CÚdric wrote:

That would make me loose speed probably, power curve is already quite peaky since power is rising all the way to red line. Looking at the power curve it would probably be better to rev to 6800, to spend more time at max power.


It was just a thought..
You might be able to talk me out of that non-limiting FPR..

CÚdric wrote:
But the 2664 is probably a bit to big for 180hp, would probably be good for another 20-40 hp safely. But it works much better than the originial 2660 when things get hot on track, with the original turbo the power got quite soft after a while.


IMO the 2660 is too small for much of anything except a city car, civilized cruiser.. Dangerous heatpump if your upping the boost especially with no IC IMO..

Iv'e ran both but don't think I upped the boost any with the 2660.. It was my first working turbo on my car, still have the compressor..

I got a bunch of good runs in with the 2664, the first compressor on my FMIC package, audi housing without the recirculating valve so it could be indexed..

It provided a few "WOW"s from passengers @14 psi before it lunched itself..
http://www.924board.org/viewtopic.php?t=41422&sid=7d911e6c951bebc25e8b1954e666d397

I'd say it's good to 1bar..


CÚdric wrote:


If I look in the KKK software I can se that the Audi quattro (200hp), Nissan Fj20ET (205hp) , ferrarri 208GTS turbo (220hp) uses the same 2664 compressor housing, just for reference.


Yep, their are many good "other" sources for these CWs, most will come with a good comp housing for indexing, no recirc..

Also, picking up just about ANY k26 is going to get you a replacement turbine wheel/shaft to fit a 931.. Very few won't work with the k26/6 951 being one of the odd ones out..
The k26/8 951 is the same turbine as all 931's too, most common/standard k26 turbine..
Turbo shops will tell you these turbines are hard to find and very expensive, and also that the old original ones are the best quality compared to $300 repops anyway.. Just check the part #s and buy a correct k26 core if you ever need a turbine..

In my experience talking to multiple turbo shops they tend to talk to you like only a professional is capable of understanding turbos, much the same as HVAC specialists..

Also they tend to put quite an emphasis on balancing, the only reason you really need a shop, but if you think about it, when these k26's were brand new this balancing technology didn't even exist, so take that for what you will..

The 2664 I lunched I torqued back to my balance marks, which wasn't all that tight, maybe loctite would have saved it, idk..

My current k26/6 compressor is on a different turbine so their was no trying to keep it balanced, torqued it to feel with loctite..
I also straightened the shaft myself to 2/10,000" with pressing V-blocks and a dial test indicator, on my current k26/6 compressor turbo..
Nabbed fresh bearings out of that audi 2664 turbo I lunched the compressor on..
Just picked the best looking thrust bearing I had, not a 360..

It's home made from parts of atleast 3 diffferent k26's and it has screamed for quite a long time with no problems at all.. Though I would still like to send it in for a balance when I'm done prototyping..

CÚdric wrote:


But im going for 2670 billet wheel anyway on the turbo im building


It will be really tought to beat him in a straight line, 935kg, super short gearing, 6spd and ca 210HP will be hard to beat. He will add LSD this winter aswell


That should be good to 30psi and might eve get you to redline in 5th if my napkin calcs are closeish.. But your not going to be able to fuel that with 931 CIS.. It will definitely take you to the limit of CIS and beyond..

That's a step bigger than mine plus whatever "custom billet" will do for you..

I'm thinking if you run that compressor with a FMIC and WB gauge, bump your system pressure to 100psi +-5psi to compensate for increased intake pressure differential vs fuel, get rid of the overboost switch, retune the mixture screw a touch, and then turn up the boost as much as you can paying attention to your AFRs @ redline with a slower sweep speed until you start to see it lean out at/close to redline, and then back a touch..

I think you may find yourself just under 20psi pushing 275-300HP ish, conservative estimate, with no electronic helpers or 5th injector sillyness..

According to my tests, http://www.924board.org/viewtopic.php?t=41465&postdays=0&postorder=asc&start=30, a 931 lambda CIS will spit out 330HP worth of fuel @100psi system, and I think that a euro non-lambda will spit even more.. But I don't know if coming close to that max is a good idea, don't know how linear delivery stays close to max, also increased boost decreasing intake to injector pressure differential, I don't really KNOW what it will actually DO up there, variables variables..

Anyway, you should easily see 250HP safely and smoke his ass..
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CÚdric  



Joined: 27 Aug 2004
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PostPosted: Thu Dec 15, 2016 6:05 pm    Post subject: Re: Dyno test, 931 vs Honda typeR K20 Reply with quote

Carrera RSR wrote:
CÚdric wrote:
He will add LSD this winter aswell


And he's getting the power down cleanly without one currently?



Nope, thats why I have a chance at 1st and 2nd gear, after that I have no chance. One other factor is im not speed shifting, since I feel I want to be kind to my gearbox, the honda gearbox is much faster.

Here it is, Honda K20 Renault 5:
https://www.youtube.com/watch?v=Ay35yo3ZRD0
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CÚdric  



Joined: 27 Aug 2004
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PostPosted: Thu Dec 15, 2016 6:17 pm    Post subject: Reply with quote

Freddie, my K26 is at a rebuild shop at the moment. I started doing the turbo work here at work (I work with gas exhange/turbo system development) but needed some more parts, and wanted to balance it. I dont trust the aftermarket wheel in that sense. And fine balancing is always good if you plan on running for full load alot of time, on a track car for example, it can make the turbo last much longer.

The 2660 is ok, got much better low end driveability with it than with the 2664, porsche chose it for the CGT aswell. But as you can notice the CGT has max power a bit lower in the rave range at 5500rpm, so it is a tad small. Especially if you want more than that.

I have no plans on maxing out the system, my goal is to have 200 hub hp (approx 220 engine hp) for a reliable track driving mode, and maybe maybe high boost 220 hub hp (240 engine) for playing around on the street. To cope with it on track im planning on a larger oil cooler and already bought a bigger radiatior. Maybe adding an EGT sensor..

Already have a knock warning light but bought a 2nd hand JS safeguard active knock control that i might wire in if I have time...
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Carrera RSR  



Joined: 08 Jan 2010
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PostPosted: Thu Dec 15, 2016 8:25 pm    Post subject: Reply with quote

CÚdric wrote:
Freddie, my K26 is at a rebuild shop at the moment. I started doing the turbo work here at work (I work with gas exhange/turbo system development) but needed some more parts, and wanted to balance it. I dont trust the aftermarket wheel in that sense. And fine balancing is always good if you plan on running for full load alot of time, on a track car for example, it can make the turbo last much longer.

The 2660 is ok, got much better low end driveability with it than with the 2664, porsche chose it for the CGT aswell. But as you can notice the CGT has max power a bit lower in the rave range at 5500rpm, so it is a tad small. Especially if you want more than that.

I have no plans on maxing out the system, my goal is to have 200 hub hp (approx 220 engine hp) for a reliable track driving mode, and maybe maybe high boost 220 hub hp (240 engine) for playing around on the street. To cope with it on track im planning on a larger oil cooler and already bought a bigger radiatior. Maybe adding an EGT sensor..

Already have a knock warning light but bought a 2nd hand JS safeguard active knock control that i might wire in if I have time...


Hi Cedric, any idea where you see the 2660 with a #6 turbine maxing out in efficiency? I wanted to install the 2670 when I rebuilt my turbo but was advised, rightly or wrongly based on all the other engine mods going on during the rebuild, not to until it was running reliably, then possibly increase the compressor volume. I have dyno'd mine at 225bhp calculated engine, with 1.0 bar boost. Feels really lively at the bottom and mid rev range. Feels like it runs out of 'pace' above 5500rpm so I don't tend to try and red line it. All the fun is from 2500-5500 rpm anyway.
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Now www.924board.org/viewtopic.php?t=34690
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CÚdric  



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PostPosted: Fri Dec 16, 2016 1:58 am    Post subject: Reply with quote

Carrera RSR wrote:
CÚdric wrote:
Freddie, my K26 is at a rebuild shop at the moment. I started doing the turbo work here at work (I work with gas exhange/turbo system development) but needed some more parts, and wanted to balance it. I dont trust the aftermarket wheel in that sense. And fine balancing is always good if you plan on running for full load alot of time, on a track car for example, it can make the turbo last much longer.

The 2660 is ok, got much better low end driveability with it than with the 2664, porsche chose it for the CGT aswell. But as you can notice the CGT has max power a bit lower in the rave range at 5500rpm, so it is a tad small. Especially if you want more than that.

I have no plans on maxing out the system, my goal is to have 200 hub hp (approx 220 engine hp) for a reliable track driving mode, and maybe maybe high boost 220 hub hp (240 engine) for playing around on the street. To cope with it on track im planning on a larger oil cooler and already bought a bigger radiatior. Maybe adding an EGT sensor..

Already have a knock warning light but bought a 2nd hand JS safeguard active knock control that i might wire in if I have time...


Hi Cedric, any idea where you see the 2660 with a #6 turbine maxing out in efficiency? I wanted to install the 2670 when I rebuilt my turbo but was advised, rightly or wrongly based on all the other engine mods going on during the rebuild, not to until it was running reliably, then possibly increase the compressor volume. I have dyno'd mine at 225bhp calculated engine, with 1.0 bar boost. Feels really lively at the bottom and mid rev range. Feels like it runs out of 'pace' above 5500rpm so I don't tend to try and red line it. All the fun is from 2500-5500 rpm anyway.


Ive never seen a map on the 2660, its a bit of an oddball. In the KKK catalouge i cant find any performance vehicles that uses that wheel, only industrial machines and ships. Only passenger that have it is Merced 300TD .

I would guess it will be quite restrained at 1bar and high flow. I chose the bigger compressor so I can run it at much lower stress, I dont want to overspeed my turbo or push it beyond design limits, that will only punish the engine more than neccesary.

I digitalized the 2664 map and used it in my 931 engine simulation model. I use a intercooler with CGT performance more or less (45degC Ic out temp). Later today or tomorrow i will come back with some simulation results with some compressor scaling. Had some issues that at 1bar the compressor moves out of the map, which isnt a good sign. So need to redo the simulations.


I looked in the KTS billet wheel catalouge, I noticed there is a bolt on wheel that fits the 2664 931 compressor, that would definitely be a good choice. An turbo aero specialist at work has ordered some wheels from them (though with his own designs) for private use and he seemed impressed with their knowledge and machine setup. Even though the webiste is horible
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