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Old 10-10-2007, 08:37 AM   #11
DINOSAURUS BOOSTUS

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How about Merlin'* LN3 Turbo car?
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Old 10-10-2007, 11:33 AM   #12
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I would not use the turbo off a diesel. First of all they weigh a ton(most are cast iron) second, I think it would have the wrong air volume for your car. Diesel engines typically run in the 25:1 compression ratio range and the exhaust pressure is way different than a gas engine. Also it takes the combined exhaust flow from 6-8 cylinders that are at least 4 times the size of your cylinders to make the turbo spool. IMHO you probably would not get the turbo to spool up or it would take way too long to be of any use.
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Old 10-11-2007, 12:17 AM   #13
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Don't use that turbo. Turbo boost is generally a little more "engine" friendly if you will, it builds compared to the on/off of an SC.

L27 can prob take a good amount of air, it'* a relatively low compression motor, decently built up. Only way to know for sure is to try it though.

Turbo size you're looking around T3, MAYBE T03/04 hybrid depending on your ultimate goals. T03 housing is a good start, go read a book or two on turbos and compressors to figure out what you need for a 231 CI engine..
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Old 10-11-2007, 03:37 AM   #14
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I'll have to admit my ignorance here, and ask the question: What makes an L27 a worse candidate for a turbo than an L36? I'd always thought that if anything, they had lightened things up with the Series II redesign? Yet there are turbo kits applied to those commonly.

I'm sure there'* something that makes it so, I just don't know what it is.
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Old 10-11-2007, 11:11 AM   #15
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Quote:
Originally Posted by theJMFC
I I'd always thought that if anything, they had lightened things up with the Series II redesign? Yet there are turbo kits applied to those commonly.

I'm sure there'* something that makes it so, I just don't know what it is.
There sure is...it;* called production numbers. L36 debuted in '95 and ran for 10 years, give or take, in MANY models. L27 on the other hand, debuted in '91 and ran only for 4 years, in far fewer models.

Truth is, none of us on this forum know just how much an L27 CAN take. We pretty much kn ow the weak link will be the pistons...spark, head temps, combustion temps, A/F ratio all have to be PERFECT in order for it to survive decent amount of boost. I'm upgrading the hell out of my hybrid engine as I likes me power, I know that there will be quite a bit of dialing in, and a custom chip will definately have to be burned to help it survive longer, but thats the price one pays
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Old 10-11-2007, 03:47 PM   #16
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Thanks for clearing that up. IF I understand correctly then, it'* more a matter of it being an engine of unknown strength, rather than a known weakness in that engine (although the popular theory is that the pistons could fail).

Difference between the L36 piston and the L27 piston? Or another factor?
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Old 10-11-2007, 04:15 PM   #17
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Not quite understanding your question. Given GM'* reluctance to change for the sake of change, I would have to say the L27 and L36 pistons are similar in the design department. L67'*, in both S1 and S2, got upgraded pistons and rods. The pistons in L67'* have their compression rings moved lower than the L27 and L36 counterparts, to reduce the chances of chipping under stress.

Armed with that knowledge, ANYONE can boost an L27 or an L36. HOWEVER, there is an inherent danger in doing so if it is not done correctly and methodlically. Very few people boost an L27 for the reason of tuning issues. L27s do not use OBDII PCMs..in fact, most are running under the jurisdiction of the GM-specific OBD 1.5 protocol, which has little to no aftermarket support. This hinders modability to a point. However, I discussed this with jr's3800, and we both agree that the 94-95 pcms, though they have that funky protocol, are way more advanced than the pre-94 PCMs and have WAY more potential.

So yes, an L27 can be boosted. How far it will go, or for how long has yet to be determined...I'm the token posterboy for those answers. But I will say this: Given ZERO runtime boosted L27 and L67'*, I can tell you after mods, the L67 will last longer.
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Old 10-11-2007, 06:26 PM   #18
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For shear boost handling, an L27 is better because it'* compression is lower @ 8.5:1. This isn't taking things into account like cam differences (prob not much, but will be some) quench area, flame propagation, etc. The L36 as a package is easier to turbo, because there are kits out for the S2, and it'* much easier to find programming solutions for the L36'*...

Until you're making some decent power out of it, a turbo L27 wont just crap out either if tuned right. If you have KR you will not last however. I'd say 5-7 PSI is PROBABLY do-able on a stock engine, but that'* almost do-able on any stock engine. Again these are all conjectures based on what I know.
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Old 10-11-2007, 09:45 PM   #19
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If you're thinking like a Dodge Cummins Diesel, thats 5.9L, it'll take you forever to spool, considering compression ratio is about 16:1- 20:1 on those engines. However, the turbo was also designed to spool up at much lower RPM'* than gas motors.
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Old 10-12-2007, 06:03 PM   #20
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If you do put on a large turbo like that, and it doesn't spool soon enough, will you still get the necessary air flow?
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