Fuel millage

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98 Nitro

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US vortec headed TBI 96 Vans are a myth. There were TBIs on G30 Vans that year but they had old school 76cc heads and were rated at 180hp.
 

L31MaxExpress

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US vortec headed TBI 96 Vans are a myth. There were TBIs on G30 Vans that year but they had old school 76cc heads and were rated at 180hp.
They are no myth. I have run across no less than 3 of them.

Also NO TBI head is 76cc, they are all ~65cc chambers. The lower compression ratio TBI engines used a different piston with a bath tub shaped piston relief.

This is the LH exhaust manifold for one. It used a longer EGR feed pipe than the the regular L31.

You must be registered for see images attach
 
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98 Nitro

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You can buy intake and exhaust manifolds from GMPP to use vortec heads on a TBI engine, everyone knows this. Stock specs for a 96 G30 van are 8.3 compression ratio with 180hp/295tq. Gm lists this as the heads on them.
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Steve Cunningham

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98 Silverado c1500, rcsb, 5.7 Vortec ,5 Speed, 3.42, stock, 235 - 75 - 15 Michelin LTX M/S 2.

12 city and 17 highway on 87 octane.

At 2000 rpm I'm doing 66mph.
 

AK49BWL

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97 Sierra K1500 ECSB, 5.7 Vortec all stock (except 12200411 swap, Hedman headers, MPFI upgrade), 5-speed NV3500, 4x4, 3.73s with 265/75R16s, electric fan swap, and a flat-top camper shell

19mpg highway, 15 city... 10 towing a 24' travel trailer :p
 

L31MaxExpress

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You can buy intake and exhaust manifolds from GMPP to use vortec heads on a TBI engine, everyone knows this. Stock specs for a 96 G30 van are 8.3 compression ratio with 180hp/295tq. Gm lists this as the heads on them.
You must be registered for see images attach

NONE of the TBI engines were 8.3:1. 8.75:1 or 9.3:1. Also these were not the GMPP intake manifolds. I know about those as well. These were the Mexico TBI Vortec intakes that had the EGR blocked off in Mexico. Where do you think the GMPP EGR plug and block off plates came from.
 

98 Nitro

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NONE of the TBI engines were 8.3:1. 8.75:1 or 9.3:1. Also these were not the GMPP intake manifolds. I know about those as well. These were the Mexico TBI Vortec intakes that had the EGR blocked off in Mexico. Where do you think the GMPP EGR plug and block off plates came from.[/QUOTE]

R&D. Maybe it was a planned stock part to go with what became the L30 305 head or maybe it is just an OTC part GM thought would make some money, like the LT1 carb intake manifold they sell, doesnt matter it was not on any stock vehicles in the US.
 

L31MaxExpress

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NONE of the TBI engines were 8.3:1. 8.75:1 or 9.3:1. Also these were not the GMPP intake manifolds. I know about those as well. These were the Mexico TBI Vortec intakes that had the EGR blocked off in Mexico. Where do you think the GMPP EGR plug and block off plates came from.

R&D. Maybe it was a planned stock part to go with what became the L30 305 head or maybe it is just an OTC part GM thought would make some money, like the LT1 carb intake manifold they sell, doesnt matter it was not on any stock vehicles in the US.[/QUOTE]

Was on some 96 G30 vans. 100% without a doubt. I worked on them back in the early 2000s. They were just high mileage delivery vans at that point. They had their own dedicated fuel system as well. The 30 psi one. The Mexico built L31s had the EGR block offs from the factory.
 

JackE

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'99 2500 Suburban with the 7.4 4.10 100% stock city 9.5, highway 10.8, towing light load same, towing heavy load 8.3, really heavy load 7.4 or lower

Out of the 400 family, but I graduated up to a '05 Escalade with the AWD 6.0 3.73 100% stock city 15.6, highway 19.8, towing a 4000 lb pop-up camper 13.3

I live in the mountains, so all numbers are with that kind of driving in mind. The one flat trip I took in the Escalade I got around 22 unloaded.
 

letitsnow

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'99 2500 Suburban with the 7.4 4.10 100% stock city 9.5, highway 10.8, towing light load same, towing heavy load 8.3, really heavy load 7.4 or lower

Out of the 400 family, but I graduated up to a '05 Escalade with the AWD 6.0 3.73 100% stock city 15.6, highway 19.8, towing a 4000 lb pop-up camper 13.3

I live in the mountains, so all numbers are with that kind of driving in mind. The one flat trip I took in the Escalade I got around 22 unloaded.

That is the only 6.0 that I've ever heard of that gets good mpg. Hard to believe. My bro in law had a similar year Escalade, it never got better than 12 mpg. He didn't have any trailers to tow.
 
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