What are legitimate expectations for exhaust,intake,tune
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With my SRT8's, Intake, exhaust and Dyno tune Was good for 25 to 30 rear wheel HP & TQ Increase. That's on the 6.1 L car that was already tuned for High performance from the factory
With the Harleys it was good for 8 to 12 hp and 12 to 15 pounds of torque And that's with a 1.6 and 1.8 L respectively. These bikes are factory tuned to pass the EPA regulations not for optimum horsepower and torque
This 2.4 L in the slingshot seems to be making slightly less horsepower and torque than Chevy advertises. I wonder if this has to do with the exhaust system that they have on it?
There may be a comparatively significant horsepower and torque gain With the intake, Exhaust and tune.
A rear wheel 15 to 20 hp and torque gain Would have a pretty significant effect on a vehicle of this weight.
With the Harleys it was good for 8 to 12 hp and 12 to 15 pounds of torque And that's with a 1.6 and 1.8 L respectively. These bikes are factory tuned to pass the EPA regulations not for optimum horsepower and torque
This 2.4 L in the slingshot seems to be making slightly less horsepower and torque than Chevy advertises. I wonder if this has to do with the exhaust system that they have on it?
There may be a comparatively significant horsepower and torque gain With the intake, Exhaust and tune.
A rear wheel 15 to 20 hp and torque gain Would have a pretty significant effect on a vehicle of this weight.
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I'm guessing around 10-15 whp with a good tune.
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yup its gonna be fast but also weird dynoing on one roller!
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I found this a tad interesting. GM says this engine has 182 hp @ 6,700 rpms. So why is Polaris publishing the horsepower ratings that the engine produces at only 6,200 rpms? The 9 "missing" horsepower is probably not missing at all. Just rev it 500 more rpms. Same goes for the torque figures. GM says 172 lb-ft @ 4,900 rpms. Polaris says 166 lb-ft @ 4,700 rpms. The "missing" 6 lbs are in the 200 rpms not being used. The dyno graphs clearly demonstrates this. Also I found interesting is that Polaris published that they're using a rev limiter that kicks in at 7,000 rpms.......... so that means that the whole rev range and capabilities of the engine is available in the Slingshot! Another thought I entertained was a little power loss while transferring the final drive from shaft>belt>tire. But that still doesn't explain the lower rpm rating. I feel pretty confident stating that this is a 180 horsepower machine. (Maybe 182! Like the manufacturer reports)
The LE5 never made more than 177HP and 173 ft/lbs. The LAF/LEA were rated at 182HP but those had direct injection which it appears the Slingshot does not. Hope that clarifies where the missing HP is, if you go on wikipedia you can search for "ecotec" and find the info for the various versions of the engine.
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I think the issue is that it isn't the LEA 2.4 motor but the LE5 which makes a little less hp/tq and is not direct injected. The LEA has 182 but the LE5 made between 169-177 depending on the vehicle it was in.
In the Solstice, which is where they say this was completely lifted from, it made 173 hp and 164 tq.
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Here is a good read for those who are not familiar with modern automotive tuning. Remember this is not a cycle so engine performance is not like what it is on a bike, but rather a car.
http://www.superchevy.com/how-to/0907gmhtp-2009-chevy-cobalt-ss-ecu-tuning/air-fuel-ratio-configuration.html
http://www.superchevy.com/how-to/0907gmhtp-2009-chevy-cobalt-ss-ecu-tuning/air-fuel-ratio-configuration.html
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So I run a 2.2 Ecotec in my dune buggy. A simple shorty header upgrade and a minor tune change with HP Tuners made a pretty noticeable difference in seat of the pants feel. I am sure that garbage pail looking muffler on the SS isn't helping matters either. There are already quite a few options for headers for these engines, and I am sure someone is going to develop something specific for the space available in the engine bay.
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Noah, when looking at that muffler and seeing all the rivets on the front side, I am thinking that is a cathlitic converter and muffler combo and is not very effective.
I sent pics of the slingshot and the muffler to Corsa and they got all excited. They said till they get a system developed, That the muffler for the BMW 1 series Might work very well, With some creative piping work from a good exhaust man
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Not true, at all. For example, a bullet style muffler is barely larger than the diameter of the incoming and outgoing pipes, and is the least restrictive muffler design there is. Lots of science goes in to exhaust design, and OEM and aftermarket design goals are different. If they weren't the aftermarket wouldn't exist.
OK, if there's a cat in there too there might not be a lot of volume for the silencing portion, though a cat silences too.
Re bullet style, fair enough, but they don't silence much.
My original statement should have been, for a given noise reduction, more volume allows less restriction.
Witness how as noise requirements got stricter, motorcycle mufflers grew in size to minimize the performance penalty.
Good to hear Corsa is interested.
I wonder if they'll think it worthwhile to make a CA or 50-state version.
Re bullet style, fair enough, but they don't silence much.
My original statement should have been, for a given noise reduction, more volume allows less restriction.
Witness how as noise requirements got stricter, motorcycle mufflers grew in size to minimize the performance penalty.
Good to hear Corsa is interested.
I wonder if they'll think it worthwhile to make a CA or 50-state version.
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I'd be interested in an aftermarket exhaust as long as it has the ability to bolt to a long tube header which is something I will be installing. If not I'll just make my own with a race style bullet muffler and a dump tube.
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