fast951

As I ALWAYS said, at 15psi on pump gas a 951 with either Stage 2 or 3 will make 310-330rwhp..
In the chart the run was stopped at 5700-5800rpm, if it was run up to 6400rpm it would have been in the 310-330 range... Install the SMT6 and fine tune the AFR a bit more, and there is some to gain... lean it out a bit over 5000 rpm and you will pick more power.
On pump gas, I do not recommend running more than 15psi boost.. I know some people run 17-18psi and they are fine. However I cannot recommend it as some cars "might" have carbon buildup on top of the pistons and 17-18psi "might" cause knock..

Switch to the race maps, and your torque goes up...

Soloracer:
- How many dyno runs did you make? Which one was this?
- Did you get a ignition misfire around 5600-5700rpm? What causes the dip in the chart?
- Why did you stop the run when you did on the RPM scale?

Looking at the graph I like the broad torque curve... There is a nice area under the curve. This what makes the car feel like a V8...

Edit: SoloRacer, if you compare your chart to the one on the website, you are fairly close to it..

- When do you hit 1 bar boost in 4th gear on the street and on the dyno?

Stage 2 comes on boost a bit sooner, so you get more torque. On pump gas, both kits perform about the same (the power band is a bit different), peak numbers are close...
On race gas and higher boost, Stage 2 will make in the 380-400rwhp.. Stage 3 can support 500rwhp. However a stock 951 (stock head, cam... will not make 500rwhp). So Stage 3 is for those that want a kit to support the most out of a 2.5l..

SoloRacer

John,

I told the dyno operator to shut down before 6000 rpm as this was the first time I had this set up on the dyno. I also wasn't sure where the rev limiter was. After the first run it didn't appear that a lot more power was coming so I decided to keep things to the 6000 rpm limit. We made 3 pulls and this one had the most power. All three were consistant though and within a few hp of each other. I just got the print out from this run.

As for when I hit 1 bar on the street I believe it's around 3300 rpm in 5th and I believe that's consistant in 4th gear as well. On the dyno I wasn't operating the car so I don't know when it was hitting 1 bar. The dyno pulls were done in 4th gear because that is the 1:1 gear. On the way home I was also wondering when 1 bar was reached on the dyno because the power seems to come on later on the graph than I would have anticipated. Could this be because the Dynojet doesn't put a load on the car?

I wasn't aware of any ignition break up but that isn't to say it wasn't happening. Hurry up with that ignition upgrade will ya? It looks like I could use it

If you remember when I drove the car for the first time with this turbo I commented that it didn't seem as on/off as the k27 which means it doesn't have the same apparent "push" that the K27 did because the power delivery is very linear. It does feel more like a normally aspirated V8 than a turbo 4 doesn't it?.

fast951

Few things to check, as your torque is a bit later than what I expected, which relates to a bit later spoolup.
- Check for exhaust leaks especially WG to X-over pipe, header to X-over and of course the headers..
- Something is going on around 5600rpm.. If you have the actual files (not the printout, it'll help).
- One of the reasons you were not making much more HP at the higher RPM it the AFR is on the rich side. I do that on purpose for safety margin... You can lean it out a bit with the SMT6..
- You can push your torque curve a bit to the left by inducing even quicker spoolup.. Again you can run a bit leaner up to 7psi boost...

Out of the box your car did fine. Not you get the most out of it by fine tuning it...

Again, as I always say, peak numbers are not that important. The area under the power curve is what makes a difference.. I rather use the average TQ across the RPM range. Take a snapshot every 400-500rpm starting at 2800rpm yp to 6400rpm. Add all the values then divide by the number of snapshots.. this is a much nicer indication of what your car is doing..
-

SoloRacer

Thanks John. I believe I have an exhaust leak also and I think the wastegate is the culprit. The installer of my wastegate could not find one of the gaskets and I told him to put it on as is. I now have a proper gasket and will install it soon.

Just for a comparison I dyno'd my 3rd gen RX7 with the stock turbos. Take a look at this chart and you can see there is a big problem. Care to guess what it is?

DDP

I don't know how the exhaust is run on the RX-7 but maybe....lol, this is a total guess....but maybe the there is an exhaust leak going to the second, larger turbo so it is late in spooling up. So when the first turbo peaks itself and turns power over to the larger turbo it hasn't yet spooled up?

Black Arrow

Ted: it was me testing the Stage 3 at 18-19psi, with very nice EGT values! Actually, its very very nice! But, I would recommend to follow Johns advice regarding boost as he`s the man who made and is selling the parts.

1bar boost at 3300 in 5 gear? Thats a bit slow? I`m getting 1bar at 3200rpm in 4 gear! In 5th its close to 3000rpm I believe.

fast951

When reading a dyno graph you can identify strong points as well as points needing attentions.. Check your exhaust, cap & rotor.. How's the clutch, any slipping? Hitting 1bar boost at the same RPM in 4th and 5th raises few questions.

As for the RX7, which I'm not familiar with. Is it a serious missfire or the second turbo kicking in (which I doubt will cause such a mess).. Why is the AFR so rich? I guess you have a bit of work to do!

As Thomas mentioned. You can run abit more boost on pump gas, and with a well sorted car you can be around 340rwhp.. However, I always advise 15psi on pump gas..

This have me thinking about moving forward with the knock display, which displays the intensity of the knock as it gets the information from the KLR.. This will be a good warning system for those that want to play with boost and pump gas.

Good thread, thank you for posting.

Herr-Kuhn

These results look good to me. Is this a K-26/8 or K-26/6 turbocharger? Peak HP is the last reason to make a purchase. I'm real close to replacing the IHI RHB-6 units in my Callaway 928 with some K-26/6 units off of the 951. With these and Euro cams I hope to make 400 WHP at 10-12 psig of boost....4.5 liter engine. I'm about to put together a 928S4 twin turbo and plan to run that at 12-15 psig to make over 600 HP. More is possible, but the life of the motor and driveline are key factors for any build. I run 24 psig of pressure in my 2.2 liter Audi, but would not consider this on a 944/928 motor. Reliability and longevity should be every bit as important as HP numbers. Anybody ever seen a piston with a shattered ring land from detonation...not pretty.

RolexNJ

Bump! That's messing the chart up. The scaling has to be off!

SoloRacer: I would go back to the operator and tell them that. I went thru the same exact thing with a Dynapack run few months ago.

streckfu's

I already answered this on page one. many graphs have the scaling offset. It is the settings on the dyno and does not imply the operator is deficient.

The HP is on the left and TQ is on the right.

jimbo1111

I think your results are pretty good. People under estimate how difficult it really is to produce good numbers such as yours. If you are never planning to run over 20 psi johns stage 2 kit seems to be the better chose. To me the best thing about johns kit is the a/f out of the box that you get. For people not willing to tinker around. This is the way to go. Stage 3 is over kill for most people. Make a wise decision as to what your goals are before you purchase. A smaller turbo looks much better when running less boost.

SoloRacer

I believe Derek had it right in that the second turbo isn't spooling when it should. The reason for that I believe is that one of the actuators that diverts exhaust to the second turbo is not functioning - possibly due to a vacuum/boost leak. I too was surprised by how rich it was. I have a stand alone EMS that plugs into the stock wiring harness (a Power FC) and I was planning on installing it soon. However, I want to make sure mechanically everything is correct first as adding the Power FC will only hide/complicate things if the car isn't up to spec now. Looks like I have to remove the intake manifold and start going through that rats nest of vacuum lines that controls the turbos. I might also consider checking out the injectors to see what size they are. I really don't know what the previous owner did to this car so I'm going to have to take a good look to see what is going on. At least the dyno confirmed what my butt dyno was saying.

Back to the 951, during the turbo install I replaced the cap, rotor, plug wires and spark plugs. I don't have any evidence that my clutch is slipping although ST here feels that the Kevlar disc won't hold. How would you know for sure if the clutch is slipping? I can put the car in top gear at 2000 rpm and it will pull all the way without any apparent slipping. I'm not sure if I'm hitting 1 bar at the same RPM in 4th and 5th. I'll do a road test today to find out.

Herr-Kuhn: The turbo is a Garrett hybrid that John at Vitesse Racing assembles and sells. The dyno from my k27/8 was much peakier (sort of looked like Mount Everest) and I'm sure the stock k26/8 would be the same. You could ask John what the turbo specs are but I doubt he will share as that is proprietary information that he spent time figuring out.

Rolex: If you go up from 5250 rpm and see where it intersects the first line (the HP Curve) and then look to the left you will see that I am making approx. 280 rwhp. Now go up to the Torque Curve and look to the right and you will see it is also at approx 280. They are the same value as they should be. As was mentioned earlier the scaling is different.

special tool

That's right - I forgot you had a kevlar disk with stock PP.
That will not be sufficient for the torque rise on that turbo at higher boost levels - nobody knows that better than I.

I made the mistake of suggesting merely a ceramic disk to friend with a high-boost persuasion - and my suggestion was not a good one.

TRWright

David Floyd

Add a KEP PP to the ceramic