Turbo v6, my ideas and hopes

[skylark]

I like it!

 

[df2x4]

The gear in my truck is no good for a V6. I assume its the stock 3.42. This is probably a good gear for a v8 with a little more low end torque but not a v6. IDK what GM was thinking... My truck pulls well from about 2500 rpm up it will outpull a v8 when the boost kicks in no problems there but from roughly 2500 down with no boost it just don't have it. I could probably live with the initial throttle response BUT what I dont like is how it cruises at 60-65 mph. Overdrive cruising puts the truck right in that ugly spot and when you come to hill or incline it wants more RPMS to keep a steady speed. The great thing about my truck is that when I give it just a few more rpms, it will build 1-2 lbs of boost which helps it along. I think a set of 3.73 gears will make a huge difference in it and actually keep it in a low boost which will help with power and economy!

As a fellow 4.3 owner with 3.42s, I feel your pain. I've actually got a Detroit Locker and 4.10s that have been kicking around the garage for over a year now that I've never gotten around to installing, need to do that one of these days.

 

[Scottydc]

As a fellow 4.3 owner with 3.42s, I feel your pain. I've actually got a Detroit Locker and 4.10s that have been kicking around the garage for over a year now that I've never gotten around to installing, need to do that one of these days.

It would def wake things up! Might suffer a little up top with a higher top gear rpm but then again it might even out with the truck not having to surge and hunt passing gear either.

 

[sewlow]

Going from 3.42's to 3.73's (29.5" tire) was one of the best, if not the best, performance mods I did to my truck when it was a V6. (Black truck. Sig.)
Didn't do that till after I'd had the truck for a number of years. Should of been one of the first things I did!
What a difference! Freeway entrance ramps? Hehe! Drop it into low, skinny pedal to the floor & let 'er go through the gears!
Then...on the brakes to slow down to enter! Lol! Freeway posted speed of 100kmh & I'd be up around 130-140kmh by the time i had to merge. Lotsa smiles per gallon!
So much nicer driving in the mountains around here. Didn't have to drop down a gear on the medium hills & the trans didn't start hunting for the right gear on the longer, steeper climbs.
The sound of the exhaust smoothed out @ reg. highway speeds, too. Sure, it was buzzing higher, but the sound was right in the sweet spot, A nice sounding purr with no resonating hum inside the cab.
Killed the mileage a bit. Actually, quite a bit! But then, that might of been because it was just so much fun to get on it!
I also ditched that Gov-Bomb & had a real Limited Slip installed @ the same time.

 

[Scottydc]

Going from 3.42's to 3.73's (29.5" tire) was one of the best, if not the best, performance mods I did to my truck when it was a V6. (Black truck. Sig.)
Didn't do that till after I'd had the truck for a number of years. Should of been one of the first things I did!
What a difference! Freeway entrance ramps? Hehe! Drop it into low, skinny pedal to the floor & let 'er go through the gears!
Then...on the brakes to slow down to enter! Lol! Freeway posted speed of 100kmh & I'd be up around 130-140kmh by the time i had to merge. Lotsa smiles per gallon!
So much nicer driving in the mountains around here. Didn't have to drop down a gear on the medium hills & the trans didn't start hunting for the right gear on the longer, steeper climbs.
The sound of the exhaust smoothed out @ reg. highway speeds, too. Sure, it was buzzing higher, but the sound was right in the sweet spot, A nice sounding purr with no resonating hum inside the cab.
Killed the mileage a bit. Actually, quite a bit! But then, that might of been because it was just so much fun to get on it!
I also ditched that Gov-Bomb & had a real Limited Slip installed @ the same time.

Nice! I am so glad to hear from someone who has done the switch! I will get a gear set ordered soon with either a locker or posi.

 

[Scottydc]

Just when things were going good, I went to data log with it and the ignition started breaking up over 4000 RPM. I also noticed that it seemed to rev slower in that range too. No backfiring or stalling just a bit of flutter and hesitation. So when I got home and looked at the scan and my eyes about popped out. "The hell?"

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Ok...I'm no rocket scientist but instinct tells me that there's absolutely no way my little 4.3 was truly turning Mazda Rx-7 kinds of rpm.... So something is definitely wrong.

It showed some really erratic behavior over 4k... I assume that my ignition module or a sensor is breaking down. Whats crazy is its affecting my timing and other settings so it's something the computer sees and is adjusting for... it's definitely no good. I've never had any luck troubleshooting ignition stuff like this. The distributor looked a little wore when I pulled it out to change the intake manifold. There's no telling when anything has been replaced and the problem is intermittent. So throwing caution in the wind I went ahead and ordered a new AC Delco Module, Accel Coil, Summit Distributor (includes new cap rotor and cam sensor) and a set of Taylor 10.5 wires. I guess all that would leave is the crank position sensor which at this point doesn't seem likely to me.

 

[94_C/1500]

I didn't read through the whole thread but what are you doing for rods? I like the 4.3L, been driving mine for nearly 10 years now but it has a severe flaw. Everyone knows its based off of the 350. But that also means its bank degree isn't the best for a V6. Originally the engine family was odd fire using the same rods as a V8. Then they switched to a 120 degree crank. Less vibrations, but weaker. Then they added balance shafts a few years later. Meanwhile a proper inline engine would've been better. Look into what a 250 and 292 can do with the lump kits.

 

[Scottydc]

I didn't read through the whole thread but what are you doing for rods? I like the 4.3L, been driving mine for nearly 10 years now but it has a severe flaw. Everyone knows its based off of the 350. But that also means its bank degree isn't the best for a V6. Originally the engine family was odd fire using the same rods as a V8. Then they switched to a 120 degree crank. Less vibrations, but weaker. Then they added balance shafts a few years later. Meanwhile a proper inline engine would've been better. Look into what a 250 and 292 can do with the lump kits.

Engine is totally stock other than the turbo and fuel system. I actually had a 250 inline in a 52 Chevrolet project that I built. I used a draw through turbo off of an early model Grand National and a TBI fuel injection setup with a Moates programmer. It ran really well. Somebody broke into my shop and stole most everything off of it. Which led me to sell the project.

 

[Scottydc]

This happened today... It will go on the engine stand and I'll slowly build it up for boost, while I'm enjoying (or destroying) the lil turbo'd 4.3

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[sewlow]

Where are you located?