View Full Version : What are the benifits of a Wastegate Turbo?
01-15-2003, 12:39 AM
We have a new guy at work with a 2wd D350 dually, I asked about the banks sticker he has on his fender and he told me he installed a banks wastegated turbo and exhaust. He's happy with the performance.<br><br>I think I have a general idea what the wastegate is supposed to do...It's supposed to let something or other bypass the system.<br><br>So is it really worth it to buy a wastegated turbo? If so, what is a economical source? What would be the damaging effects, if any, from not having a WG turbo?<br><br>Thanks,<br>Joe V
01-15-2003, 02:34 AM
Believe it or not, there are times when too much boost can be a bad thing...
The wastegate serves to relieve excess boost pressure at a preset limit. If you over drive a turbo, you can actually overspool it, you can develope high/extreme drive pressures, and cause your 'charge air' temps to be too high for the intercooler to handle effectively. (that assumes you have an intercooler, if not then you will see some very high boost air temps going into the engine and that is not good.)
This will drive engine exhaust temps up big time.
Drive pressure is the amount of pressure applied at the inlet to the exhaust side of the turbo,.. if that climbs too high it can be well in excess of the actual 'boost side' of the system. This is basically backpressure and results in nasty temps.
I'm certainly no expert on this, but I've come to learn that you only need enough boost to burn the fuel supplied, thats all.
Remember there is a difference between boost and volume. You want lots of air volume and minimal boost pressure to keep your charge air (boost air) temps low.
Each turbo has it's own 'efficiency map' and performs best when it stays within that map range. So, you use a wastegate to limit upper end boost pressures.
You can also limit boost pressure with fueling levels. Usually more fuel developes more exhaust gasses and you have higher boost levels.
You can run without a wastegate if you are prepared to adjust fueling and throttle levels to keep it in control. (No fun!)
The exhaust housing side (were it connects to the exhaust manifold) can range from a 21cm to as small as 12cm. The smaller the housing, the faster it winds up (spool up). The smaller it is, the sooner you will find it 'runs out of air' or starts developing high drive pressures.
Common aftermarket housing sizes range from 16cm to 12cm. Most of the Banks kits were 14cm wastegated housings. Anything smaller than 16cm requires the exhaust downpipe to be modified a bit. You have to cut about 1 1/4" inches off the upper end and re-attach the connector end to the shortend downpipe. The reason is the tail end of the 14cm and the 12cm housings are longer by that much.
Usually you will find the 14cm housing comes wastegated, but there are some available without a wastegate. I have one to go on my truck (currently running a 16cm NW) When uprating fueling and towing heavy the 16cm is the more common housing used since it gives decent spooling and good boost at the upper end without too much drivepressure increase.
If you want absolutely 1st class help, parts, info go here...
Talk to Piers or Al.
Does that help???
01-16-2003, 01:37 AM
Thanks Bob, <br>that does explain things. I noticed a 16cm NW is the standard upgrade for our 1st gens due to it being a bolt in, what kind of mods are necessary for a 16cm WG and where are decent priced used ones located?
01-16-2003, 02:42 PM
I personally have never seen a wastegated 16cm housing.<br>Every one that I've ever come across has been a NW'd housing.<br>They are cheap even brand new. You may come across one if someone is changing out to a smaller 14cm or 12cm.<br>Keep your eyes peeled in the parts forums.<br>Currently my 16 is generating about 28psi for me, and that is on winter fuel, and with backed off pump settings.<br><br>Sorry I couldn't be more help with that. If I come across a 16 I'll shoot you a PM right away.<br><br>Bob.
01-16-2003, 07:38 PM
Joe,<br> I've seen the NEW 16cm housings on E-bay for only $135.00. They come and go, so you'll have to watch. They are being sold by some one out in Arizona, I think. Click on E-bay and type in dodge cummins in the search bar.
01-16-2003, 09:37 PM
If you're gonna do that, then contact Piers at PDR. He will be competitive and he'll also include all the gaskets you're going to need, the one's on E-bay don't.<br><br>www.piersdiesel.com<br><br>bob.
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