Maker of twin-turbo kit for Corvette claiming massive (167%) city MPG increase.

[pgfpro]

I hate to discredit anyone when it comes to making something better. I really hope that this company's claims are real.

IMHO I believe that any engine can improve on performance and FE when you run a turbo charger with a manditory programmable engine management system. I have seen this with the cars I have tuned and others that have been tuned by someone else first hand.

Now in this case as far as their HP claims I have no problem believing in their HP numbers. Major HP gains with turbos are being done all the time. With the turbos their running and the Corvette engine this should be pretty easy. The changes I would make...throw away the FMU and install larger injectors. FMU's are a cheap way to flow more fuel and are very hard on the injectors themselves.

Now as for the mpg claims I can see that its possible but my question is why aren't they getting a better freeway number when they are getting a extremely good city number? This part really confuses me???
The city part of the fuel and ignition maps are by far the hardest to tune for performance and FE. The freeway part is the easiest to tune. So one would think their freeway mileage would be a lot better then what they advertise?

[Frank Lee]

For one thing it looks like they aren't making anything; they are merely installers and marketers.

For another, who gets that level of HP and fe increase with up to 6 psi boost- the level they registered with CARB? Boost from the back of the car isn't magic; it's still just boost.

You shouldn't be confused by their numbers once you realize they are all made up.

[tjts1]

This looks like a cheap knock off of an STS turbo setup which is patented. While the STS turbo system is innovative in terms of packaging, it doesn't make any outlandish fuel economy claims. Its purely a performance product.
http://www.ststurbo.com/

[Big Dave]

This is so monumentally bogus that it doesn't merit discussion.

[Christ]

Originally Posted by pgfpro

I hate to discredit anyone when it comes to making something better. I really hope that this company's claims are real.

IMHO I believe that any engine can improve on performance and FE when you run a turbo charger with a manditory programmable engine management system. I have seen this with the cars I have tuned and others that have been tuned by someone else first hand.

Now in this case as far as their HP claims I have no problem believing in their HP numbers. Major HP gains with turbos are being done all the time. With the turbos their running and the Corvette engine this should be pretty easy. The changes I would make...throw away the FMU and install larger injectors. FMU's are a cheap way to flow more fuel and are very hard on the injectors themselves.

Now as for the mpg claims I can see that its possible but my question is why aren't they getting a better freeway number when they are getting a extremely good city number? This part really confuses me???
The city part of the fuel and ignition maps are by far the hardest to tune for performance and FE. The freeway part is the easiest to tune. So one would think their freeway mileage would be a lot better then what they advertise?

They're driving in the city at under 2400 RPM. The highway (and performance) tuning takes place at a higher RPM range, so no point in tuning below that.

They're able to claim increased efficiency (as with any turbo setup) because the mix runs slightly lean below the tuned point.


These are assumptions, of course. I have no idea how/if they tested.
One commonly forgotten thing about turbos is that they're ALWAYS working, as long as your foot is on the throttle. Just because you're not showing positive boost doesn't mean the turbocharger isn't doing anything - its' still pumping air, just not enough volume to create pressure in the intake. The engine still doesn't have to work as hard to suck in air, though, since there is more of an atmosphere readily available at the throttle plate. This means that more air is getting in than would normally be sucked in under the engine's vacuum, and thus, less pumping losses. Better low-speed FE comes from 2 things - less load on the engine, and leaner AFR, usually. The latter isn't always true, when EFI systems are self-monitoring, but most times, noone tunes standalones that low, so they end up with a stock basemap with tuning on top of it, and run slightly lean at low speed/throttle angles.

By the way, I got the honker. Good Gods, man. That thing is massive.

[pgfpro]

By the way, I got the honker. Good Gods, man. That thing is massive.

I'm glad to hear it got there. It is massive, my index finger can still its mass. LOL

On the city driving tuning the thing that is a pain in the arse when trying to conserve fuel is the accelerator pump part of the software. Stop and go traffic can kill your FE because of this.

But there are ways you can get around this if you don't mind having a lean stumble.

[Christ]

Originally Posted by pgfpro

I'm glad to hear it got there. It is massive, my index finger can still its mass. LOL

On the city driving tuning the thing that is a pain in the arse when trying to conserve fuel is the accelerator pump part of the software. Stop and go traffic can kill your FE because of this.

But there are ways you can get around this if you don't mind having a lean stumble.

Any time I tuned a turbo car (not too many, but a few) I never even touch the basemap below about 2500 RPM. The turbo never spools any lower than that, regardless of load, so I always just left that part out. Besides, if you're racing (which was the whole point of the turbo setups I was tuning), you seldom see engine speeds under 2500 anyway, if at all.

[dwtaylorpdx]

650 is not much power, the 09 Z06/7 makes 638.

I worked on a Z06 last year and with nothing but a different tune from GM it made 490.

I wonder if their system is a Turbo-Normalized setup not a pure turbo?

I know planes that have a turbo normalization kit get better mileage than full turbo planes.

Dave

[Christ]

Originally Posted by dwtaylorpdx

650 is not much power, the 09 Z06/7 makes 638.

I worked on a Z06 last year and with nothing but a different tune from GM it made 490.

I wonder if their system is a Turbo-Normalized setup not a pure turbo?

I know planes that have a turbo normalization kit get better mileage than full turbo planes.

Dave

The '08 MY was rated 436/428... 650 is a huge jump for a street car.

[Frank Lee]

Ground vehicles get normalized?