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Got boost?

Started by Rx7man, February 16, 2016, 10:15:31 AM

65fpvmustang

Have you thought about a fuel cut. I read on ecomodders where a 5.9 was getting some crazy mpg.
He had a fuel cut switch on his shifter.
I have a fuel cut on ranger 3 second delay and tps and rpm min.
Good for 2-3 mpg where i live, nothing is flat.
If i could get 40k at 2800 I would be very excited.

Rx7man

It'll definitely be different on a gas than a diesel since a gas engine cuts the air supply.

Don't know how I'd go about implementing a fuel cut on my truck, or how it would save fuel... the governor will cut fuel anyhow if you let off the throttle at cruise RPM... What I did find saved a lot of fuel was to despool the turbo at cruise.. so when I'm under about 30% TPS and above 2000 RPM, the turbo is set to pretty much wide open, reducing drive pressure... I picked up a fair bit of mileage at highway speeds on flat ground with it.. I got 500 miles on a tank of mixed city/highway driving and thats with 4.10 gears.. Highway speeds were about 75mph, so I wasn't snailing along either.
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

65fpvmustang

I didn't know the gov would cut fuel below idle. So that guy was only cutting idle fuel when coasting.
I wouldn't ever cut engine in coast around here. Be a good way to see the bottom of a scenic canyon.
Are you using vgt closed for engine warm up?

Rx7man

You can cut fuel on a gas engine with no adverse effects, the engine is still turning and powering the steering, and creating vacuum for the brakes.. Most modern vehicles probably do that already.

I usually just hit the engine brake when it's cold.. I have to do some tweaking on it since the jake switch will double as a 'high boost' switch, so that when I'm preparing to pass, it'll spool the turbo up.. It'll probably do something like command to 50% of normal mode nozzle size.  I have it implemented, but not tuned
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

65fpvmustang

spool switch is awesome
I can hit 50k at 3500 rpm 55mph maintaining speed. gives 5psi ready to rock
wanted to try dropping to second gear 4500 rpm but already scared crap out of son.

Rx7man

haha!  I scared the fellow that I did the governor springs for I think.. nearly doing 4 wheel drifts on the side of a cliff might do it
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

65fpvmustang

I did a couple light pulls showed him how it brought the turbo shaft speed up.
I had just picked him up from his mom's and she messes with his head makes him think everything is better at her house. doesn't help he is 13 and cocky. So he wasn't impressed with the pull at 2800. He told me how fast his mom's hemi truck gets up to speed only thing the mpg suck. I explain how not many people work a gas engine this hard at this low of rpm.
So at the next straight I did the 3rd gear 3500 rpm to 4600 pull. hit 19 psi before i let off. Told him that was about 300hp maybe 350. Son "Wow that hurt my neck". We get to my favorite spot. at least a 1/4 mile uphill stretch slight turn to right leaving from a stop sign. I tell him to watch the tach. I run through the gears shifting at 4500 then tell him peak power is around 6500 rpm. There is another 150-200hp left.
Don't think i'll be hearing about the hemi anytime soon. ;D

Rx7man

Hehe, sounds like fun... Makes me miss my old Rx7.. handled like it was on rails, and 400 (more now) RWHP in 2500 lbs sure moves you.. 400hp was at 11 psi with a T68-1, I am going to try to convince my buddy to put a VGT on it.. the car started to spool around 3000, and it was full on by 3600 all the way to 7500
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles


Rx7man

I can't watch videos from here.. I'll try and remember to watch it next time I get decent internet
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

65fpvmustang

he351ve on 13b 12 psi neutral rev

only thing is want to run air mass meter exhaust pressure changes messes with speed density.

I real think a 3L with he351 would be nice street car. something around 200hp NA.
but rotory's are the exception 13b be perfect fit. ;D

Rx7man

I have a street ported 12A that's got about 10 miles on it since it was rebuilt.. Had a supercharger on it, but I think a turbo would flow soooo much more.

I could definitely see how large changes in exhaust pressure could mess with speed density, though if your turbo acts consistently you should be able to find a happy medium. 
You might have to limit the drive pressure to a certain amount over boost to prevent it from becoming a large factor?


I think the biggest problem about a 351 vgt on a 13B is once it's up to boost, I think you'd still need a wastegate.
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

Rx7man

I think this was the old, bagged out engine
https://www.youtube.com/watch?v=g9DnwFnqO6I

And this one was the new engine, though it wasn't tuned yet, and had serious issues with fuel puddling, which causes all the bogs and bad idle.. If I was able to go EFI I'd have been able to solve those problems.

https://www.youtube.com/watch?v=KwrpENRYf64
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

65fpvmustang

12a would be good if it has ceramic apex seals to take the heat.
my friend has a 13b rx7 nice paint and ground effects but china 54mm turbo.
i have been working on him for years to put a  he351ve on it. he is a garret guy 6.0 power stroke is his truck. quick but not very reliable.

Rx7man

Ceramic seals are apparently no good for boost.. too brittle.  it has 3mm steel seals.  Buddy was running 45 PSI boost on steel 2mm seals (they were $200 a piece 10 years ago) and made 875 RWHP.. they can handle it if they're good seals.

I attached a pic of the turbo I had

'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles