Turbo Dyno Sheet

[Stephen]

I just got my car back from Webb Motorsports (Littleton, CO). Randy Webb put in the latest version of the Unichip (I believe it is called the Q version???). This took care of the stalling issues that I had with my car. Idle is steady at both cold and warm temps and I have not had it stall a single time in almost 1000 miles now. My ForcedFed turbo kit (which Randy installed back in February) has close to 5K miles on it with no issues. Randy tuned my car with the new chip and I have posted the dyno results for your information. Randy does top notch work, I highly recommend him for any engine upgrades you wish to do.

[sleepless]

Interesting torque/power curves. Can someone that is good at calculating shift point determine if one would shift before redline on this setup?

[edge007]

a/f ration seems lean at the bottom. Is this through the stock injectors? What fuel pressure are you running?

[Bane]

Originally Posted by edge007

a/f ration seems lean at the bottom. Is this through the stock injectors? What fuel pressure are you running?

Holy crap you think?!

That doesn't seem lean... that looks downright scary to me. I used to tune my turbo vehicles for 11.5:1 if they were to see any street duty. We'd venture close to 12:1 for race cars on 110 octane.

[keith86a]

Look at the power and torque curves, no turbo lag whats so ever and the power delivery is as linear as they get. I can also confirm this from personal experience, aside from the noise, forcedfed turbo elise feels and drives like a supercharged car.

[keith86a]

Originally Posted by Stan

You can't tell that from the plots...

Look at the torque curve, its almost a straight 45 degree line, indicating no noticable power surges and a smooth delivery. Also look at the boost, at 3.5k rpm its almost at full boost. I can also add that these graphs do confirm what it actually feels like on the road. Full boost before 4k rpm, and smooth power delivery from then on. There is instant thortle response over 3k rpm, even a slight touch on the pedal produces instant acceleration, you can tell its under full boost by that point. As you can tell, the cam transition is also much smoother. GT28R is simply perfect for this application.

[Bane]

Originally Posted by Stan

You can't tell lag from that chart. What you are desribing above is not the whole picture. You can look into this stuff further with a data logger.

lol. Is the data logger the answer the life's questions?

You could tell what kind of lag it had if the graph had time as one of the axes.

[Andrikos]

Would that be a graph that has Power on the Y axis, Time on X and a bunch of curves from 0 - 100% (WOT) throttle opening?
Kindof like transistor curves.
Does that make any sense?

[keith86a]

Originally Posted by Andrikos

Would that be a graph that has Power on the Y axis, Time on X and a bunch of curves from 0 - 100% (WOT) throttle opening?
Kindof like transistor curves.
Does that make any sense?

I'm no expert, but I never saw such a graph (I dont think its very common?). Personally, I think the above graphs are enough to determine the characteristics of power delivery, smoothness, etc. Usually, with turbocharged cars, you see a sudden increase, sometimes as much as 100%+ over short rpm ranges. Take high hp supra's dyno for example. On this dyno, power doubles between 4k rpm and 5k rpm, so you can tell that this car has a lot of lag:


Now compare it to the elise and you can clearly see the difference. Also, according to hassturbo.com, the GT28R is fully boosted by 2.5-3k rpm on this engine, which is also confirmed by the above data. Again, this is all confirmed by actually driving the car, you dont have to be an expert to "feel" that the turbo is fully spooled by 3k rpm.

[sleepless]

Graph is too noisy below 3K to see the turbo spool up. Looks like they started the dyno run just below 3K. As you say, by then it is fully spooled up. Would have been nice to see it from 2K to see how the power delivery is. But frankly, who drives this car below 3K? So it's a bit moot. Still, it will only tell you the power delivery characteristics under straight line accel. Only a test drive or some data logs will tell you how it delivers power in some twisties.

[keith86a]

Originally Posted by sleepless

Graph is too noisy below 3K to see the turbo spool up. Looks like they started the dyno run just below 3K. As you say, by then it is fully spooled up. Would have been nice to see it from 2K to see how the power delivery is. But frankly, who drives this car below 3K? So it's a bit moot. Still, it will only tell you the power delivery characteristics under straight line accel. Only a test drive or some data logs will tell you how it delivers power in some twisties.

Here is another 275 dyno (along with stock), but again, cant tell much below 3k rpm. Its plenty powerful below 3k rpm, you can get the car of the line without even giving it gas.

[edge007]

Look at the a/f on this turbo car and you will see that it is around 12:1 or under. The a/f in your car is at around 15:1. That is pushing the lean side. My turbo car (not elise) runs around 11:1, the extral fuel is used to cool the motor. Leaning the mixture is a way to increase horsepower but it brings along much higher exhaust temps, which could melt your exhaust valves or burn holes in the tops of the pistons.

Originally Posted by keith86a

Here is another 275 dyno (along with stock), but again, cant tell much below 3k rpm. Its plenty powerful below 3k rpm, you can get the car of the line without even giving it gas.

[Bane]

Originally Posted by Stan

I showed a quickie example when Scottyb and I played with my NA car and his Turbo Elise.

In this case each car was quickly floored from 2000 RPMs or so. At first the NA car would shoot ahead. If you try various combinations of starting RPM and throttle position you can get a better feel for things.

The WOT dynos that show when a turbo kicks in after being run floored from much lower RPMs are not telling the full story. For example if you were in a given gear cruising along and then floored it...you would NOT hit the torques shown in your WOT dyno instantly. You'd hit some lower figure and build to the final figure. This can take 3/4 second to 1.5 seconds on many cars in the less favorable RPM ranges. In the favorable ranges you still have some lag but it tends to be lower.

For example in one of the tunes that Scott and I compared..if you floored it from 2000 something RPMs in each car..at first the NA car would pull 2 feet on the boosted car. And then a few seconds later the Turbo car would make up about 8 feet by the top of second, winding up about 6 feet or 1/2 car length ahead. That is not the full potential of the turbo, but it was what each car could do that day. For one thing that particular turbo setup and tune had little more than stock on the cam.

Did the turbo car have different low-compression pistons? There should be little to no difference in how they react initially when the gas is stood on given you have identicle motors with one having a turbocharger hanging on the exhaust side.

It almost looks like someone tuned the turbo car real conservatively pulling a lot of timing down low to try and avoid detonation under heavy load and low RPM. Try it again with more aggresively set timing and race fuel on the turbo car and see what happens

There is little to NO power gain in leaning the fuel on a turbocharged car out by the way. All you do is risk damage for a tiny bit of return.

[scottyb]

Originally Posted by Bane

Did the turbo car have different low-compression pistons? There should be little to no difference in how they react initially when the gas is stood on given you have identicle motors with one having a turbocharger hanging on the exhaust side.

It almost looks like someone tuned the turbo car real conservatively pulling a lot of timing down low to try and avoid detonation under heavy load and low RPM. Try it again with more aggresively set timing and race fuel on the turbo car and see what happens

There is little to NO power gain in leaning the fuel on a turbocharged car out by the way. All you do is risk damage for a tiny bit of return.

That tune was early on to see what I could max out at the cam change over to see if I could compensate for a very restrictive exhaust. In fact it had a hiccup at the cam change over. My later tunes were much more responsive at lower rpms.

[fzust]

Any more updated graphs? Was this using race gas?

[Stephen]

Originally Posted by fzust

Any more updated graphs? Was this using race gas?

No updated graphs. This was on a mix of about 96 octane gas. I currently run 101 octane.

[PWR2W8]

I'll be on the dyno jet Thursday early morning. can you find out what settings they ran your car at? What cd did they use, car weight etc..

Thanks!

Originally Posted by 05EliseNM

I just got my car back from Webb Motorsports (Littleton, CO). Randy Webb put in the latest version of the Unichip (I believe it is called the Q version???). This took care of the stalling issues that I had with my car. Idle is steady at both cold and warm temps and I have not had it stall a single time in almost 1000 miles now. My ForcedFed turbo kit (which Randy installed back in February) has close to 5K miles on it with no issues. Randy tuned my car with the new chip and I have posted the dyno results for your information. Randy does top notch work, I highly recommend him for any engine upgrades you wish to do.