Banks 6.2L Turbo Lag

[jggiedeman]

Morning all,

I've got a pretty fresh engine, properly set-up fuel system, 5 speed manual, etc. I bought a Banks system with the intention of needing extra boost getting over small mountains with a TT. Works fine in those aspects. What I would like is some advice on handling the Banks "Lag". She spools up later than I would like which causes brown smoke out of my exhaust taking off from every stoplight. Has anyone changed their 6.2L Banks turbo over to a turbo that spools faster? I'm not looking for more power but just want to change the powerband of this thing. I've read about some folks moving to a TE06 Banks but those can be hard to find.

Thanks,

[gmctd]

GM-8 works wonders in the off-idle power band - requires new down-pipe, but that shouldn't be no hill fer a stepper.

Might also help if you'd stop referring to that brawny Diesel truck as "she" - unless, of course, your taste in women runs to big Russian women wrestlers.................;)

[DmaxMaverick]

Without switching to a wastegated turbo, you won't loose the lag. Some non-wastegated turbos are better than others, but the difference isn't at all remarkable. The smoke will be there no matter which turbo you use. The duration of the smoke is dependent on the lag.

A wastegated turbo can spool faster, but the reason is a smaller housing. This will loose efficiency at higher RPM's and power levels, which makes them less econimical, and increases sensitivity to EGT's. At best, even they will lag only a little less than what you have now.

You can reduce take-off smoke, though. It is caused by a bunch of fuel getting dumped in before the boost comes up. A little patients and less foot feed will reduce it. The pump, if adjusted for the turbo, has been turned up, which increases the maximum fuel volume output. This is only present at the WOT end of the pedal. So, don't use WOT at take offs, and wait for the turbo to spool up before matting it.

You can also play with the pump timing to optimize the power/smoke/spool equation. Be sure to have an EGT gage in place before getting away from original settings, though. Generally, it will be a trade-off. Improve one area, and another falls off.


Options...........
Determine your primary needs, independent of the actual performance.

Mostly towing and distance traveling is best served with what you have now, or an upgrade of the same type of turbo. Improvements won't be night and day, but you can optimize your economy, towing power, and EGT's. The lag and take-off smoke won't go away.

Mostly short trips and city driving may be best with a wastegated turbo. Spool is much quicker, but you will sacrifice top end efficiency, and likely have to manage EGT's and hills differently. You may be sacrificing your long grade abilities due to increased EGT's, ECT's and lower sustainable power levels. The lag and smoke will be less, but you will still have some.

One last option is dual turbos. You could have the best of both worlds, but it is costly, and just more stuff to go wrong.

[doncannon]

Hello All,

jggiedeman: I have a 6.2 put on a reman 6.5 injectors and pump. There is not much turbo lag. What kinda rig do you have and mileage? I know i was not getting that much boost before now it is 12 lbs. and no muffler. My lil hot rod...he he he

Let us know,
Don

[gmctd]

You are seeing more lag because of the manual trans - impossible to "stage" for more low-rpm exhaust energy.

You would see somewhat less of a problem with the constant-loading of the automatic trans.

Imo, the GM-8 would give excellent service on your 6.2 with the 5-speed, very similar to the Mitsu TE06H, with Bill Heath's manual wastegate controller

[grape]

Call Dave at majestic turbo in dallas, tell him you want an .81 A/R "Euro" p trim housing............bolt's on. Stock banks is a 1.0 A/R.

[grape]

[QUOTE=DmaxMaverick]A wastegated turbo can spool faster, but the reason is a smaller housing. This will loose efficiency at higher RPM's and power levels, which makes them less econimical, and increases sensitivity to EGT's. At best, even they will lag only a little less than what you have now.

QUOTE]

a real wastegate isnt' in the exhaust housing, that thing that people call a wastegate in an internally gated t3 exhaust is about big enough for a 2 litre honda. If you have enough volume to bypass the turbine up top, you can have the best of both worlds.........

Mine's at 12 pounds by 14-1500 and gets on the gate at 14 pounds by 1600.........with a .68 exhaust housing

[ronniejoe]

a real wastegate isnt' in the exhaust housing, that thing that people call a wastegate in an internally gated t3 exhaust is about big enough for a 2 litre honda. If you have enough volume to bypass the turbine up top, you can have the best of both worlds.........

Mine's at 12 pounds by 14-1500 and gets on the gate at 14 pounds by 1600.........with a .68 exhaust housing

Not to mention the flow distortion caused by integral wastegates. The only advantage that they have is that they are self contained and easier to package. From a performance standpoint, they are mostly a negative.

[john8662]

Find the A/R ratio on the exhaust housing of your current turbo.

There were two that were packaged by Banks, I've tried them both.

The 1.15 and the 1.0.

Both are Dogs IMHO, because they are a T04B style turbo with a reasonably large exhaust housing.

Grape is right, shoot for a .81-.86 ratio.

The ATS kit I played with for a little while was in this range and screamed.

Finding that .81 is hard though. I managed to find one out of High Tech Turbo, but it was approximatly 300 bucks. The kicker is that the Banks downpipe uses a 6-bolt flange.

If you don't mind modifying the downpipe a little, installing a 4-bolt flange on the pipe then finding a 4-bolt exhaust outlet housing would be easier. That way you can almost certainly get the a/r your'e looking for.

Sticks are a difficult with these turbo's though.

Forget about the recommendation of the GM-8 turbo. there isn't a way to get that turbo to even fit in that area. The exhaust outlet points at a 90* angle from the turbo, it will be facing the cylinder head. You'd have to completly cut the elbow, then weld (on cast by the way) and it wouldn't be really worth the effort. I think someone on here always rags on PatrickM for welding on cast, I wonder who...

I'm swapping to TE06H, but I gotta fix the tranny in the '86 first, cause it don't like no Turbo 6.2 very much...

J

[ronniejoe]

Whats wrong with welding cast iron? It's done all the time. I've done it.

[john8662]

Whats wrong with welding cast iron? It's done all the time. I've done it.

I didn't say I wouldn't do it...

[jggiedeman]

Thanks for the great info. I do like the stick but didn't realize that the turbo needed a constant load. Has anyone tried a different size crossover with a different turbo for the Banks system? Or should I just leave it like that and find a .81 - .86 A/R turbo?

Jerry G

[grape]

just buy an exhaust housing........

talk to george up at Turbo Technology, he's up in your area, he might have something laying around.

[john8662]

Your crossover should be 2" already, mandrel.

I made a 2.25" crossover that's not like Banks crossover (different routing path, instead of RIGHT BESIDE THE PAN), but I have more lag than I want too, maybe due to the x-over being larger. I'll find out soon as I'm having the same crossover fabricated but with 2".