So i have a chance to pick up a s475 for a great price which may allow me to run compounds sooner than i thought. If i stick with the stock hx35 would the s475 be a good match or am i going to wish i went with something smaller?

 

Anyway studs and injectors are getting installed this week but i have some turbo decisions to make.

 

Option 1: Stick with the original plan and buy a s362 for now and compounds later down the road. ( if i go this route i would probably run a s472 as the larger turbo.)

Option 2: Pick up the s475 and run it under the hx35 right away.

 

 

Also does anyone know if the egt probe that comes with the Quadzilla is the same as the comes with the Isspro ev2 gauges? I have been having consistently low readings so i swapped them around and now the quad is reading low. Im thinking its just a bad probe and hopefully not the gauge.

 

Thanks for all the help guys, yall have been a great help so far.

 

 

HX35 over a 475 is a popular combination. Lots of people like it for towing, but the HX will be your limiting factor. I haven't looked into the 472 enough to know how it compares to a 475, but my 475 is a great primary. I opted to put tighter exhaust housings on my turbos to bring torque on earlier. 

But, your first step should be to evaluate your goals for the truck. Once you have an idea of what horsepower or capabilities you want, then we can guide you better

Pretty unlikely you’re egt probe is bad. Between Isspro and quads are basically identical except for the connections back to the gauge. If two different probes are giving you the same reading then that’s probably correct. If you think they’re low when they should be higher, maybe the probe isn’t installed far enough or the seal is no good, or perhaps you have it on the front 3cyl on the manifold?

I'm running a S475 / HX35W combo, I love it. Spools quick and it's a breeze with towing. I towed a trailer from NM to Washington state about 6 months back and rarely ever got over 1000*F. 

If you really want to run compounds right out of the gate you can, but if you ever want to switch turbos you'll have to find a new intermmediate hot pipe between the two turbos since the HX35 has a replacement exhaust elbow to meet up with the S475.

7 hours ago, trreed said:

HX35 over a 475 is a popular combination. Lots of people like it for towing, but the HX will be your limiting factor. I haven't looked into the 472 enough to know how it compares to a 475, but my 475 is a great primary. I opted to put tighter exhaust housings on my turbos to bring torque on earlier. 

But, your first step should be to evaluate your goals for the truck. Once you have an idea of what horsepower or capabilities you want, then we can guide you better

Would like to be in the 500hp range. Compounds make the most since for me since my truck is a welding rig that weighs in north of 11k on a daily basis. I’ve tried to update my sig but still no luck. 

 

Truck specs as follows:

2002 3500 HO

6spd with 550 hp vailair clutch

4in exhaust, quadzilla with v2

fass 150 and isspro fuel, egt and boost. 

 

Orderd studs and 7x.011 injectors that will go in this weekend. 

6 hours ago, notlimah said:

Pretty unlikely you’re egt probe is bad. Between Isspro and quads are basically identical except for the connections back to the gauge. If two different probes are giving you the same reading then that’s probably correct. If you think they’re low when they should be higher, maybe the probe isn’t installed far enough or the seal is no good, or perhaps you have it on the front 3cyl on the manifold?

Here is how the probes are set up. Now that I think about it I remember having to cut the leads on the isspro gauge when I was removing it from my old totaled f250. So possibly a bad connection/ground. The low temp moved from the isspro gauge to the quad when I switched the probes. 

 

Quad always read higher. Now it reads lower.  Even with full wire tap it was tough to break 1100 on the isspro where as now I have no issue seeing 13 to 1400 on the gauge if I push it hard with wiretap on. 

6 hours ago, Cronus577 said:

I'm running a S475 / HX35W combo, I love it. Spools quick and it's a breeze with towing. I towed a trailer from NM to Washington state about 6 months back and rarely ever got over 1000*F. 

If you really want to run compounds right out of the gate you can, but if you ever want to switch turbos you'll have to find a new intermmediate hot pipe between the two turbos since the HX35 has a replacement exhaust elbow to meet up with the S475.

I will probably be building the piping myself either way. I’m a welder by trade and tig welding carbon or stainless is not an issue. I really need the quick spooling of the hx for my weight but don’t want to choke out the top end for crushing and general horsing around. 

 

The s475 is a box turbo at this point so I would be swapping out to a gated 12cm housing anyway. 

Those numbers sound right for EGTs. My guess is cutting the wires messed with the expected resistance to the gauge and is causing the lower temp reading which is why on the uncut quad probe you’re seeing higher (but normal) temps.

1 hour ago, KMayborn said:

I will probably be building the piping myself either way. I’m a welder by trade and tig welding carbon or stainless is not an issue. I really need the quick spooling of the hx for my weight but don’t want to choke out the top end for crushing and general horsing around. 

 

The s475 is a box turbo at this point so I would be swapping out to a gated 12cm housing anyway.

HX35/475 and 7x0.011's will put you right around your goal.  Already having the V2 tuning is a huge plus too.  HX also already has a gated 12 cm housing.  A box 475 will work just fine, but your low end torque would be a touch lower than say a 475 with a 1.15 exhaust housing.

2 hours ago, notlimah said:

Those numbers sound right for EGTs. My guess is cutting the wires messed with the expected resistance to the gauge and is causing the lower temp reading which is why on the uncut quad probe you’re seeing higher (but normal) temps.

I didn’t change the wiring to the gauge just the pigtails on the probes themselves. That’s why I’m thinking the probe. 

 

My my buddy has the ev2s also so I’m gonna snag his probe and see for the read the same. 

2 hours ago, trreed said:

HX35/475 and 7x0.011's will put you right around your goal.  Already having the V2 tuning is a huge plus too.  HX also already has a gated 12 cm housing.  A box 475 will work just fine, but your low end torque would be a touch lower than say a 475 with a 1.15 exhaust housing.

 

Much rather have the torque with my heavy ***** so I’m gonna swap the housing to a 1.15 on the s475. Shouldn’t I have a gate on larger turbo tho? The housing in there right now is non gated. 

Edited May 8, 20186 yr by KMayborn

Leave the primary non-gated.  Secondary is as much gate as you'll need on a VP truck.

Just remember, the more torque, the better of a chance you'll break something.

3 hours ago, trreed said:

Leave the primary non-gated.  Secondary is as much gate as you'll need on a VP truck.

Just remember, the more torque, the better of a chance you'll break something.

 

WHAT? You mean these trucks aren’t bullet proof? Lol

 

So what’s the reasoning around not running the gate on the primary? Just not enough fuel to to build too much boost? Sorry if it’s a stupid question I just don’t know a lot about turbos and compounds for that matter. 

@jlbayes is probably the best one to ask, but it's because you have a T6 mounting flange and a large A/R ratio, so there's no chance of overspeeding the primary.  Whereas a stock HX35 has a T3 foot and a .70 A/R ratio.  Smaller the A/R ratio, the faster the gases spin through the housing and turn the turbine.  So wastegates exist to allow excess exhaust gas (especially when larger injectors are added to the mix and the total mass of gas increases) to bypass the whole housing and avoid overspeeding the rotating assembly, so it doesn't blow up and send metal through everything.

Soooooooo not all "s472s" are created equal. Exducer sizes and other features in the compressor will make a difference. 

 

Unless you plan on running a t4 primary (do not recommend) there is no use for a gate on a t6 housing. It moves enough mass flow.

9 hours ago, jlbayes said:

Soooooooo not all "s472s" are created equal. Exducer sizes and other features in the compressor will make a difference. 

 

Unless you plan on running a t4 primary (do not recommend) there is no use for a gate on a t6 housing. It moves enough mass flow.

Gotcha. So I found out this s475 turbo actually has a 1.37 ar or the 18cm housing. So I should definetly swap it out? That being the case should I go with the 12 or the 14. 

There is no direct conversion for a/r ratio to cm2 as a/r ratio is based off of the turbine wheel diameter. Just a fyi.

 

You would want a 1.15 T6 available from Borg Warner.

3 hours ago, jlbayes said:

There is no direct conversion for a/r ratio to cm2 as a/r ratio is based off of the turbine wheel diameter. Just a fyi.

 

You would want a 1.15 T6 available from Borg Warner.

 

I see. I’ll add that to the list of parts to order. 

s475 and 1.15 would be much more responsive than a 1.32AR.

 

If you truly do not plan on going past 500HP the s464 with 83 turbine and 1.10T6 housing will be cheaper and spool faster.