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hx 35 turbo

My only concern with ATT on THIS is if I run it through a fairly large ATA( just because I can...:D) will it suffer substantial lag ? Otherwise it sounds like the way to go. Initially I probably won't run an ATA anyway as I really want to see how hot it will get towing with the old school rad and puny 6.2 WP. I am planning on swapping the front of the motor over to all 6.5 accys since a 12v conversion is in order anyway. It should all work. the reason I have always loved GM is they make everything interchangable. What other vehichle could you swap a 1983 steering box into a 1969 ? (with minor hose adj)
 
JiFaire said:
And that there is the difference - good post, Rhino.

Chicago, I would kill to have a Penninsular 18:1 setup with a holset like you're running (by the way, is it an HY35 (like you said) or an HX35 (ilike in your sig)? - there is a difference, for those wanting to build their own.)

However, I think Turbine Doc's point was, as rhino mentioned, about a stock engine (21:1) - just swapping the turbo, nothing else. We know the ATT is suited really well for that application and that the efficiency profile matches the engine needs. Anything bigger, we probably need an intercooler and some way to restrict boost levels, in my opinion.

Of course, I've been wrong before :D
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I have been swapping back and forth with the HX and HY. Just depending on my mood :smile5:

Lately, I have been driving long distances a lot the HY shows better milage on the highway.

I guess the point that I have been trying to make is that if you want a 6.5 that makes great power, gets great fuel economy and will have solid reliability, spend the money (if you have it) and go to 18:1 with more boost. That way, the turbo is doing the work to make power and not the crank-rod-piston, trying to compress more gas.

I cruise at 75 with 10-12 psi and the turbo is making the power to keep the truck moving at that speed. And in doing so, the truck makes no black smoke under load and the fuel economy is phenomenal (for an IDI engine).

I would just like to know who is getting a LEGITIMATE 22 MPG? And hell, if my set-up was in a 1/2 ton or non-lifted 3/4 ton, it would be even better.

I am not saying anything is wrong with the ATT or 21:1 but if anybody every has the opportunity, which about 1 out of 4 here do when they end up blowing their engine, to just make the switch to 18:1.

I mean hell, I wonder what the ATT would do on an 18:1 engine? The compressor might be a little small but if you had an S engine and mech. pump, it might work great.

I have been around for a while and not to toot my own horn but I have pioneered some great stuff as far as ATA inter-coolers, larger turbos and big exhaust setups. And in doing all of this, I have put over 50K miles on my rig with the 18:1 motor and high boost with zero issues.

With that said, I just want people who have the option to consider the fact that if you want to spend a shinny nickle on an engine, go with a lower compression and let the turbo do the work and not the engine.

Look at the drag racing world. The fastest cars out there on the strip have forced air. No more high compression nitrous motors. ANything that is going 8's in the 1/4 mile has a turbo, big blower or two turbos. And they last all season unlike 15:1 gas motors that have to get rebuilt every other weekend.

My $.02
 
Chicago TDP said:
I mean hell, I wonder what the ATT would do on an 18:1 engine? The compressor might be a little small but if you had an S engine and mech. pump, it might work great.
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Dennis aka Slim Shady is running 18:1 with ATT, said if he had to do again he would be at stock CR,

Thing I like about the ATT it is bolt on, and operates in the design limits of the engine, at 100mph I'm only using 10 psi boost to do it, no excess stresses requiring lowered CR, I run out of fuel before running out of boost or EGT margin
 
I have been running an 18:1 engine with the ATT turbo for over 20,000 miles. where the ATT and the 18:1 shine is towing, if I towed all the time I would be using the 18:1 engine and the ATT turbo. This combination netted me 11 miles to the gallon towing over 1000 miles in a weekend on all driving conditions.

The engine has great grunt at lower rpm up to 1400, I was towing a 27000 lbs truck and trailer combined, and at 65 to 70 miles an hour. There is a picture in my garage of the load. I ran 7 to 10 psi boost almost all of the time and could get 18 psi at full throttle up a hill. The truck ran beautiful towing and would live a long time doing it.

Now if I was not a towing freak, I would go back to the 19 or 21 to one compression for the added efficiency achieved without the extra boost. I know the 18 to one was designed for marine applications to limit the piston wear at sustained rpm of 2700 to 3200 rpm under undulating loads. Prop in and out of the water or modulating stress loads. Road trucks are different, not that much spool up to 3200 rpm unless you race your truck.

The ATT works fine for both and does not add to the retained heat by needing an intercooler to be efficient. Nothing wrong with the Holset just different ways of doing things.

I like the least amount of back pressure, intake air temp, along with the most cfm at the least pressure. Engineers will tell you that you can never achieve over 100 percent efficiency, others argue the turbo does that. I can't say either way, We have a lot of R$D that says the turbo works, and consistent data that shows most people see from 1 to 3 mpg increase without any modifications to the engine other than a free flowing exhaust.

The turbo is a straight bolt on and uses all of the stock hardware, no need to make or fabricate any new parts. That is a pretty sweet deal for 740.00 plus shipping, for a brand new high precision manufactured turbo for our engine.

Just my two cents, I can't make the turbo any cheaper than I have and continue to sell them. They certainly are on par with a rebuilt factory turbo as far as price, If you also notice the price of rebuilt factory turbos has come down because of the ATT, the GM 4 used to be 800 to 900 dollars for a factory rebuilt. Why do that when you can up your efficiency and fuel mileage with a ATT turbo, and save your motor from excessive back pressure.

Do you have any exhaust back pressure readings for the Holset at different compressor pressure readings.?

By the way I have a five speed with 4.10 gears and regularly see 18 to 19 mpg at 68 mph or 2368 rpms. I also run quite bit at 2500 rpm when empty and see 17 mpg with a five speed.
 
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Slim Shady said:
I have been running an 18:1 engine with the ATT turbo for over 20,000 miles. where the ATT and the 18:1 shine is towing, if I towed all the time I would be using the 18:1 engine and the ATT turbo. This combination netted me 11 miles to the gallon towing over 1000 miles in a weekend on all driving conditions.

The engine has great grunt at lower rpm up to 1400, I was towing a 27000 lbs truck and trailer combined, and at 65 to 70 miles an hour. There is a picture in my garage of the load. I ran 7 to 10 psi boost almost all of the time and could get 18 psi at full throttle up a hill. The truck ran beautiful towing and would live a long time doing it.

Now if I was not a towing freak, I would go back to the 19 or 21 to one compression for the added efficiency achieved without the extra boost. I know the 18 to one was designed for marine applications to limit the piston wear at sustained rpm of 2700 to 3200 rpm under undulating loads. Prop in and out of the water or modulating stress loads. Road trucks are different, not that much spool up to 3200 rpm unless you race your truck.

The ATT works fine for both and does not add to the retained heat by needing an intercooler to be efficient. Nothing wrong with the Holset just different ways of doing things.

I like the least amount of back pressure, intake air temp, along with the most cfm at the least pressure. Engineers will tell you that you can never achieve over 100 percent efficiency, others argue the turbo does that. I can't say either way, We have a lot of R$D that says the turbo works, and consistent data that shows most people see from 1 to 3 mpg increase without any modifications to the engine other than a free flowing exhaust.

The turbo is a straight bolt on and uses all of the stock hardware, no need to make or fabricate any new parts. That is a pretty sweet deal for 740.00 plus shipping, for a brand new high precision manufactured turbo for our engine.

Just my two cents, I can't make the turbo any cheaper than I have and continue to sell them. They certainly are on par with a rebuilt factory turbo as far as price, If you also notice the price of rebuilt factory turbos has come down because of the ATT, the GM 4 used to be 800 to 900 dollars for a factory rebuilt. Why do that when you can up your efficiency and fuel mileage with a ATT turbo, and save your motor from excessive back pressure.

Do you have any exhaust back pressure readings for the Holset at different compressor pressure readings.?

By the way I have a five speed with 4.10 gears and regularly see 18 to 19 mpg at 68 mph or 2368 rpms. I also run quite bit at 2500 rpm when empty and see 17 mpg with a five speed.
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I would just like to add that it has been my experience that a free flowing exhaust does NOT increase fuel mileage (by itself) on a relatively un-modded daily driver. Towing, fueling modifications, and a heavy right foot renders all bets off...

The point? The ATT turbo is the reason that Dennis is seeing these MPG improvements.

Regards,
 
Chicago TDP said:
Just to throw it out there, I have tuned my truck a little more accurately and have gotten 22 MPG on my last long trip (320 miles) with 0 stops.

So just to let everyone know, there is a solid combo out there that can make great power, last long and get great milage.

I was actually scared to drive the truck because at I had gone 250 miles on half a tank and have never done that in my life. Thought the gas gauge was off.

The truck also has a 3" life, 33" BFG AT's and a fiberglass topper on the bed.

And the truck had about 150 pounds of ammo, 50 pounds of guns, chairs, a folding table, two guys and a cat.:smile5:
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Chicago - How about a few photos in your album at this site. I know you did a major paint/interior overhaul. Love to see it.
 
Veg_Out said:
Chicago - How about a few photos in your album at this site. I know you did a major paint/interior overhaul. Love to see it.
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I will grab some photo's off of my laptop.

Yea, it was about $5k and 3 months to do a frame off with my truck. Totally worth it though, better then a $700 a month truck payment.
 
Chicago TDP said:
I will grab some photo's off of my laptop.

Yea, it was about $5k and 3 months to do a frame off with my truck. Totally worth it though, better then a $700 a month truck payment.
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when my truck starts getting bad thats what im doing. just dont like the look of new trucks
 
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