Thread: Supercharging a 4BD1

Originally Posted by c.h.i.e.f

Just wondering if when you said air/fuel ratio leans the egt's go high i thought leaner was cleaner and cooler for diesels ? I probably misunderstood your post though not the first time and probably not the last

John just wrote it the other way around to normal.
I always talk fuel/air ratios where leaner is colder, he was talking air/fuel ratios which leaner is hotter. Same thing just upside down.

Series3. The Chev 6.5 is pox. The duramax is good, which isn't surprising since it's an Isuzu.

Originally Posted by Dougal

John just wrote it the other way around to normal.
I always talk fuel/air ratios where leaner is colder, he was talking air/fuel ratios which leaner is hotter. Same thing just upside down.

Series3. The Chev 6.5 is pox. The duramax is good, which isn't surprising since it's an Isuzu.

Auh gotcha now...I misinterpreted it... I word it as you described though hence my confusion...
I agree the 6.5 is crap same as the 6.2 I'm not to sure about the 7.3 power stroke but as for the duramax it is a very nice bit of engineering from what I've read.

Originally Posted by c.h.i.e.f

Just wondering if when you said air/fuel ratio leans the egt's go high i thought leaner was cleaner and cooler for diesels ? I probably misunderstood your post though not the first time and probably not the last

Thanks, I had a brain fart there while I was thinking of reduced air - now fixed.

Well you can supercharge a diesel. The 6.5 Chev and the 6.6 Duramax come with the option of being supercharged but the are V8 not 4 cyl. So does it make a difference, the V8 probably runs a bit smoother than the 4BD1. These are just examples of supercharged diesels.

Originally Posted by Series3 GT

Well you can supercharge a diesel. The 6.5 Chev and the 6.6 Duramax come with the option of being supercharged but the are V8 not 4 cyl. So does it make a difference, the V8 probably runs a bit smoother than the 4BD1. These are just examples of supercharged diesels.

ah yes we never said you couldn't it is just why would you?? iirc the aftermarket duramax centrifugal blower kits are used in addition to turbocharging, to reduce the horrific lag these big engines have. heaps of boost too, 40+ psi has been quoted

jc

True, I wonder how well a variable vain turbo would bolt on. Even a twin turbo kit, a big one for high revs and a small one for low revs that would get rid of the turbo lag.

Originally Posted by Series3 GT

True, I wonder how well a variable vain turbo would bolt on. Even a twin turbo kit, a big one for high revs and a small one for low revs that would get rid of the turbo lag.

yes, a compound turbocharger set up will be a way better option than super/turbo.

jc

Originally Posted by Series3 GT

Well you can supercharge a diesel. The 6.5 Chev and the 6.6 Duramax come with the option of being supercharged but the are V8 not 4 cyl. So does it make a difference, the V8 probably runs a bit smoother than the 4BD1. These are just examples of supercharged diesels.

There were no factory supercharged 6.5 GMC or 6.6 Duramax diesels.