Turbo-matching explained.
Turbo matching is probably THE most important thing to do when it comes to building any type of turbo race car. Anything from Le-mans to your simple street set-up it's integral that you pick and choose and do some R & D for the turbo set up.
Putting a GIGANTIC turbo onto the car and then doing a quick street tune, butt-dyno isn't going to do you any good. To understand this you have to know a little about how turbos work.
An engine is essentially a big air compressor. The intake manifold "sucks" in air and the exhaust ports shoot them out. The way a turbo works is that instead of the exhaust gases being let freely out the rear of the car, a turbo is put between the exhaust ports and somewhere before the exiting portion of the exhaust.
The turbo is spun by the exhaust port gases, this process combined with the air that the turbine in the turbo housing sucks up creates a combine vaccuum force that pressurizes and eventually when it hits a certain amount of pressure is released into the piping that heads back to your intake manifold.
A smaller turbo will spin faster and get to that certain point faster but not push as much air no matter how many PSI's it's running. How much boost you're running doesn't help with anything if you don't know what kind of turbo setup someone is using.. A bigger turbo will spin slower but will force more air into an engine at a lower amount of PSI. Of course things such as displacement and engine size comes into play, but let's not worry about that for right now. The spinning of the turbo is regularly known as spool or spooling. Not to be confused with Spooning. However one must also realize that both will spin around the same speed when fully spooled, but large turbos generally take more time to get there.
Turbo matching is important because of a few things: 1. Powerband. It helps to put you into the right kind of powerband you want. 2. Efficieny. You don't want a turbo that spools 3 days from now only to make like 250hp when you can do that much faster with a smaller turbo. And 3. Cost. Bigger turbos generally will cost more.
I can't tell you which turbo you should go with, that's all personal preference. However I can put into perspective as to how important it is to match your turbo to your engine size.
Let's say that Mike Lane and I are going to have a sprint run around a track. Since I couldn't get a hold of Mr. Lane while writing this, let's say for the sake of arugment that Mike wears a size 14 in mens. I wear a size 10 in mens. We get up to the starting line and Mike decides to put all 220lbs of his manly canadian muscle into a size 12 shoe. I step up to the plate, with all 145lbs, and am strapped snuggly into a size 12 shoe also, waiting for the light to turn green. The sun shines on my bronze skin as the wind sweeps across his pale sweat-swept body. We flex our muscles and wait for the go.
The light turns green and we're off! Mike thunders down the strip with all 220lbs of muscle beating the ground like an earthquake the whole way through while I majestically and swiftly take off. I reach the end before he does and win the race for the universe. But why? I mean he's a mounty for cripes sake, shouldn't he be able to run faster than me? Of course, he probably does run faster than me in real life. But he wasn't able to use his full potential. Then again neither was I. But I had more potential to use all of my ability while Mike was stifled with his ability. This is what it's like for a small displacement engine to get a big turbo it can't spool very well and a large displacement engine getting a small turbo that it'll "over-spool."
So we start the race again, this time I'm wearing size 10 shoes and Mike's wearing his size 14's. This time we're there with our A game. We're wearing a loose fit jersey with cute matching shorts. We both line up and glare at each other as the gravel beneath our fingers tremble with anticipation. The gun booms and we take off! I sprint with all my heart and reach the finish line before Mike. He gets mad and throw a brick at me and wins by default. But the question here is, why did I win again? Well it was all in the tuning, I had some Nike pumps while Mike was wearing some Addidas. I was able to turn up the boost in my pumps and manage to not only keep up but also pass him. This is much like tuning. Just because the displacement is larger and can do more it doesn't necessarily mean that they'll beat you. It's all in the tuning. I can still increase my ability to run with certain modifications and/or spend more time training/modding myself to go faster.
I hope this has somehow helped any of you. Good day and good night.
-Chris
Last edited by Sirc; 03-03-2005 at 01:57 AM.
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