Intake manifolds.

[Ziegelsteinfaust]

I have decided to turn my C10 into a more DD friendly vehicle. While I do miss the 475hp on tap, and awesome pulls to 6500 rpm. The basic rebuilt LT1 with 400hp roughly is such a nice driver. It has even got me thinking of swapping out the 4.88 gears for 3.73's. I feel dirty.


While not in the near term budget. I want to finish swapping it to fuel injection which is already 1/2 way done.

The mid 90's LT1 uses a short ram intake designed for hood clearance. Which didn't seem to hurt the big B-bodies economy at all.

Richard Holdener says from his testing that really low rpm is not dependent on manifold design. Like 2000-2500 rpm, and below. Engine dynamics are the determining factor.

So does anyone think TPI intake would do anything for mpg? Or that if I do it. I would just gain a good bit of low end torque, and cut off the top end.

Thoughts opinions

[AussieinNC]

The best MPG improvements can be had with a lighter right foot and excluding those "awesome pulls to 6500 rpm"

[Ziegelsteinfaust]

Originally Posted by AussieinNC

The best MPG improvements can be had with a lighter right foot and excluding those "awesome pulls to 6500 rpm"

Please reread the post, and let's not be captain obvious

[mattfranklin]

Just some random thoughts... With a TPI and injection you'd have less maldistribution of fuel. That could lead toward better MPG. I've always liked the looks of those manifolds, both the older long tube and later shorter tube styles. Torque and power curves are always a combination of tube length and diameter, cam lift and timing, and head design. If there isn't enough perceived low end torque, just grab a lower gear.

Best bet is to experiment. Get one of those apps for your smart phone and test it. Record 0-60 times. Remember to correct for air temp, humidity, and barometric pressure, so you're comparing apples to apples. Make only one change at a time. Have fun learning.

[Accelo]

TPI intake would do anything for mpg? Or that if I do it. I would just gain a good bit of low end torque, and cut off the top end.

I think it may be a mistake to use a radical came with the TPI. The manifold doesn't have enough flow to take advantage of a camshaft above 224 duration at .050.

You didn't mention the transmission. Changing the gears will make a huge difference in mileage, especially if you are not running an overdrive transmission.

Seems you currently have a fun sport truck. Turning it into a daily driver should be easy enough and should enhance the livability a bunch.

[Ziegelsteinfaust]

Originally Posted by Accelo

TPI intake would do anything for mpg? Or that if I do it. I would just gain a good bit of low end torque, and cut off the top end.

I think it may be a mistake to use a radical came with the TPI. The manifold doesn't have enough flow to take advantage of a camshaft above 224 duration at .050.

You didn't mention the transmission. Changing the gears will make a huge difference in mileage, especially if you are not running an overdrive transmission.

Seems you currently have a fun sport truck. Turning it into a daily driver should be easy enough and should enhance the livability a bunch.

My cam is a stock Corvette cam with 1.6 rockers. So it's very mild.

I have a Th700, and will switch to 4L65 for fuel injection at minimum.

May do 6L80 since I can keep my acceleration, and get mpg. If I do that I will just keep the mini ram intake to keep rpm gain a little better at speed.

I honestly haven't driven it on the freeway much to get a read on mpg. If it's anywhere in the 18-20 range. Which it should easily be. The original 383 that died when the trans blew up got 18-20. With a bigger smog legal cam, and a Holley 750 vacuum secondary. So I don't see why I shouldn't get slightly more. I will put off to finish up other projects I need to get rid of.

[Ziegelsteinfaust]

Originally Posted by mattfranklin

Just some random thoughts... With a TPI and injection you'd have less maldistribution of fuel. That could lead toward better MPG. I've always liked the looks of those manifolds, both the older long tube and later shorter tube styles. Torque and power curves are always a combination of tube length and diameter, cam lift and timing, and head design. If there isn't enough perceived low end torque, just grab a lower gear.

Best bet is to experiment. Get one of those apps for your smart phone and test it. Record 0-60 times. Remember to correct for air temp, humidity, and barometric pressure, so you're comparing apples to apples. Make only one change at a time. Have fun learning.

As of today. My dad wants a tpi 383 in the truck were building him. Since I showed him the Richard Holdener tpi showdown. He is liking the fat torque curve for the truck. Since it will be his DD, and tow pig. I am looking at the First tpi unit for what ever engine. If I were doing it for mine. I would weld up 1/3 the runner to gain broader power.

Although I will use a smaller B body cam with 1.6 rockers. Which should match nicely for smooth driving, and torque. That a 80 year old man could want.

Like I said in the above post the old 383 got 18-20 highway.

So if this combo gets 20 highway. I won't likely change just the gears due to my 2500 non lock up converter. There will be little to no gains due to increased slippage. So I will just save to go all the way when I am ready. Instead of rushing it to much. Since I get good mpg city like 15-17. Which is where I drive the most.

Although now I want a more adult truck. I can live with it for awhile longer.