HX40 vs. ATT

[Nick Gustafson]

So, I've come to the recent realization that my HX35 isn't really cutting it in the airflow department, so I'm considering upgrading to a slightly larger turbo. I've got two options, both of which have similar prices to me right now; a genuine HX40 with a 16cm housing, and an ATT. Either way, they'll be run with WMI, 3" intake plenum, and more than likely an intercooler. Not really looking for high boost numbers, but I'm trying to keep it in the 15-20 psi range. Any thoughts/opinions on either of these setups are appreciated since I'm trying to figure out the most efficient option for my truck.

 

[Twisted Steel Performance]

The 12cm turbine is what's holding you up.....

You already have 1/2 the ideal turbo, change the blade & compressor side and you will have a hybrid 35/40... much less money spent and no change required to the down pipe...

Hunt up a 14cm hx35 turbine hws, a used hx40 compressor cover , and a different set of blades and your set.... lots less cash and you can do it all yourself...

Or by something new...

You have a DS4 IP I'm guessing so a different tune may be needed...

 

[Nick Gustafson]

By the time I get the blade and comp side of the hx40, as well as get the CHRA machined to accept it, and find the elusive 14cm housing, i'll have as much into that hybrid as I would if i went and got the hx40 and everything needed to install it. The tune will be changed, but that's easy enough to do.

I do agree though, the 12cm is probably what's holding me up the most, as well as skyrocketing IATs

 

[Twisted Steel Performance]

How ya figure that?? The chra is the same ... what machining, I've built several...

What do you want, fast spool & lots of air or slower spool and more smoke ?

Most will say go the phone turbo way or a true hx40, maybe that will work for you, If ya ever rode in my last truck & motor, or another similar, it would change your thinking me thinks....

Your cash not mine, good luck....

 

[Nick Gustafson]

From what I've seen and have been told, I'd have to get the backing plate machined to accept the larger compressor wheel. Price wise, 14cm housings are between 120-180 from what I've seen, and the new wheel and comp housings are around 260 from what I can find. It seems I'll be spending roughly 400-500 regardless. Not trying to get more smoke, i can blackout an intersection if I really want to right now with the 12cm. I want more pulling power in the higher rpms. I think that with the long gears, and a larger exhaust housing, it'll be a good match. I could be wrong though

 

[JayTheCPA]

One advantage of the ATT is that an intercooler is not necessary. So less complexity.

In terms of smoke, with a recent tune for the ATT, sometimes I get some when I first stomp on it. As soon as the boost comes in it is hard to see any.

 

[FellowTraveler]

One advantage of the ATT is that an intercooler is not necessary. So less complexity.

In terms of smoke, with a recent tune for the ATT, sometimes I get some when I first stomp on it. As soon as the boost comes in it is hard to see any.

What kind of egt's you seeing @ wot towing?

 

[JayTheCPA]

Have seen up to the 1200 range with the RV in tow, A/C 'On', and climbing ~6% grades. At best I will only let it stay that high for a short time as that level of power will push up the ECT's.

Empty, it is difficult to get much over 1000.

 

[FellowTraveler]

Have seen up to the 1200 range with the RV in tow, A/C 'On', and climbing ~6% grades. At best I will only let it stay that high for a short time as that level of power will push up the ECT's.

Empty, it is difficult to get much over 1000.

I suspect you would see overall better performance with a cac/ic.
As ECT'S go I'll see a 10/20 deg f rise sometimes at 70+ mph w/ac on and outside roadway heat radiating reading of 105+ deg f....

 

[Quadstar Tuning LLC]

In terms of smoke, with a recent tune for the ATT, sometimes I get some when I first stomp on it. As soon as the boost comes in it is hard to see any.

OBDII in general is easier to tune out the smoke because there's 2 different tables to reference fuel and timing to MAP pressure. Nick could control the smoke more with his right foot when he want's to ; )

 

[6.5L]

I'm slowly building my next turbo bit by bit. Helps save spending a lot of money at once. Also a route to go if you want to big custom design.

 

[Hink]

Ditto with the no smoke on the ATT. I can make it smoke when I try, but with normal operation it's not an issue.

With the hammer down, and a bit of a load (going uphill), I've had the needle bouncing a bit around 22 PSI. I see pretty regular 18-20 PSI on that same hill.

 

[tanman_2006]

I pulled the spool valve off today (never ran with out it on my 93) and going to try to get a base line/feel for it by itself then throw the spool back in after I get some fueling issues figured out.