Very small 12 valve tow twins

In my opinion, a spool flange on the bigger down stream turbo will slow down initial spool-up which will translate to slower overall spool up because the tighter the big down stream turbo, the more it affects the smaller manifold turbo. The turbine wheels gets power two ways: 1. extracting heat energy from the exhaust flow, and 2. extracting kinetic energy from the exhaust flow which translates to pressure drop across the turbine. The more restrictive the downstream turbo, the less pressure drop across the turbine wheel of the small manifold charger.

As a single turbo, the HE351 initially spools faster than the HX35 due to the 351's smaller/lighter turbine wheel and 9cm housing. Around 5 psi, the HX35 surpasses the 351, and then around 18-20 psi the HE351 takes over and out paces the HX35 in both spool-up and air flow.

If I had a spare HX35, I'd use it. If I didn't have an extra turbo laying around, I'd get an HE351. If you want maximum power and wastegating potential, get the HE351.
 
Find a 475 with a 1.10 t4 foot 83/74 turbine, I have a hx35 over that turbo and it's very responsive. Feels every bit of 600hp, im in the process of finding the right 480 to drop in place of the 75.
 
Big Blue24 said:
In my opinion, a spool flange on the bigger down stream turbo will slow down initial spool-up which will translate to slower overall spool up because the tighter the big down stream turbo, the more it affects the smaller manifold turbo.
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I saw this in the turbo test I did...starting the dyno runs from 1500rpm netted 1,041 lb-ft with a 57mm as a single, and 950 lb-ft with 57mm/71mm twins. The single was all done at about 450hp though.
 
Big Blue24 said:
In my opinion, a spool flange on the bigger down stream turbo will slow down initial spool-up which will translate to slower overall spool up because the tighter the big down stream turbo, the more it affects the smaller manifold turbo. The turbine wheels gets power two ways: 1. extracting heat energy from the exhaust flow, and 2. extracting kinetic energy from the exhaust flow which translates to pressure drop across the turbine. The more restrictive the downstream turbo, the less pressure drop across the turbine wheel of the small manifold charger.
Click to expand...

I didn't think of that. Makes complete sense though.

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You could PM Extended Power about using a spool flange on the primary.
 
Ghostman said:
i can buy a brand new BW 363 for $450
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53523-Arnold-Schwarzenegger-Conan-Ba-hgfF.gif
 
Smokem said:
You could PM Extended Power about using a spool flange on the primary.
Click to expand...

Thanks, i will.



Even with slowing down the secondary, would the benefit of the sped up primary out weigh it?

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JQmile said:
I saw this in the turbo test I did...starting the dyno runs from 1500rpm netted 1,041 lb-ft with a 57mm as a single, and 950 lb-ft with 57mm/71mm twins. The single was all done at about 450hp though.
Click to expand...

What size 71mm did you use?

I've got a brand new 57mm with a 12cm housing sitting at the house that I had planned on using in a small twins setup but I'm not sure if I'm going to use it any more since I'm looking to sell the truck.

I had planned on using a 72/83-1.10 under the 57 as a small towing/street twins. I had wanted something that spooled FAST and kept the smoke off my bay boat!
 
In my opinion, 80% of the useable street/towing/smoke control power curve is determined by the small manifold charger. Once the small charger is making 20-25 psi boost, the motor acts like a big cube engine as far as exhaust flow and the difference between a S472, S475, HT3B, HT60, in terms of spool up is small ie 20% factor in useable power. Once the little turbo starts to peak around 400 rwhp, then the big atmosphere turbo is the major driving factor in peak power, egt control, smoke clean up, etc.

The one added benefit I have personally noticed with small twins HX35/12cm over HT60/20cm is the tight HT60 exhaust housing causes the HT60 to spool a little earlier in the power band which helps with flat-land towing 8-10 psi total boost and cruising 5-7 psi total boost egt readings more so than looser/bigger atmosphere turbo setups I've tried in the past. On the hills, there is enough exhaust flow to spool up the bigger S475/1.32, HT3B/32cm setups so bottom turbo selection is really only a factor in total horsepower potential. I do notice the 0-5 psi total boost response (HX35's initial spool-up) is slower with the tight HT60 vs. other HX35 twins setups I've tried out with more traditional 26cm+ exhaust housings or S400's with 1.32AR housings.

One last tidbit, I'm having difficulty breaking 550 HP with the HX35/HT60-20cm combination. It feels like the exhaust side is too restrictive for big power. I'm still testing and tuning and discovering all the factors involved but my early results look like 20cm housing on the HT60 is causing excessive back pressure in the 500+ HP range. The 20cm housing is nice for cruising boost because it makes 2 psi between stages at 10psi total on the slight grades but it also gives up quite a bit of power on the top end.
 
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SuperDave4x4 said:
What size 71mm did you use?

I've got a brand new 57mm with a 12cm housing sitting at the house that I had planned on using in a small twins setup but I'm not sure if I'm going to use it any more since I'm looking to sell the truck.

I had planned on using a 72/83-1.10 under the 57 as a small towing/street twins. I had wanted something that spooled FAST and kept the smoke off my bay boat!
Click to expand...

The 71 is k31 based (Aurora 5000) and I actually think it spools a little too quick...but the response seems very good once the rpms are up. For instance, if the truck makes a shift into OD and locks the converter at say half throttle, it drops all the way to 1,500rpm but the turbos are still making about 20psi. The engine pulls through it without any surging. I had originally planned to push these small chargers to see how much power I could make with them, and this thread is kind of renewing my interest in that. If I could make, say, 800rwhp or so with a 57/71 combo, I think it would freak a lot of people out...:Cheer:
 
Convertor selection means as much as turbo selection. I can build 30 of boost towing locked in overdrive. Going threw the gears it doesn't build this kind of boost as fast but my thinking is once locked everything is hot allowing for the extra boost. Moving off the line with the tight convertor I ease into it to avoid to much smoke. Of course all this has to do with the outside air temps and how hot the motor is. To just say it makes 30 lbs. of boost locked at 1500 is not a true statement.

The 01 with the 341 over 3b spools fast, not as fast as the hy35 single it replaced but fast. Probably 100 or more rpm's faster than the 351 I started with but the convertor is not as tight in it.

I don't have a pressure reading between stages but the 351 is gated at 26 give or take a lb. or two. With the 160 pump racked barrels and 5x.012 injectors it maxes out around 58 lbs. of boost. I would like more but it stays together this way and it is my main work truck.
 
I need to say, 30 lbs. with a loaded trailer making the motor work. It varies but I've seen 30 a lot. I will usually back out of it or shift out of OD to not lug the motor this hard.
 
Big Blue24 said:
In my opinion, 80% of the useable street/towing/smoke control power curve is determined by the small manifold charger. Once the small charger is making 20-25 psi boost, the motor acts like a big cube engine as far as exhaust flow and the difference between a S472, S475, HT3B, HT60, in terms of spool up is small ie 20% factor in useable power. Once the little turbo starts to peak around 400 rwhp, then the big atmosphere turbo is the major driving factor in peak power, egt control, smoke clean up, etc.

The one added benefit I have personally noticed with small twins HX35/12cm over HT60/20cm is the tight HT60 exhaust housing causes the HT60 to spool a little earlier in the power band which helps with flat-land towing 8-10 psi total boost and cruising 5-7 psi total boost egt readings more so than looser/bigger atmosphere turbo setups I've tried in the past. On the hills, there is enough exhaust flow to spool up the bigger S475/1.32, HT3B/32cm setups so bottom turbo selection is really only a factor in total horsepower potential. I do notice the 0-5 psi total boost response (HX35's initial spool-up) is slower with the tight HT60 vs. other HX35 twins setups I've tried out with more traditional 26cm+ exhaust housings or S400's with 1.32AR housings.

One last tidbit, I'm having difficulty breaking 550 HP with the HX35/HT60-20cm combination. It feels like the exhaust side is too restrictive for big power. I'm still testing and tuning and discovering all the factors involved but my early results look like 20cm housing on the HT60 is causing excessive back pressure in the 500+ HP range. The 20cm housing is nice for cruising boost because it makes 2 psi between stages at 10psi total on the slight grades but it also gives up quite a bit of power on the top end.
Click to expand...

So I'm still twin retarded here, but it sounds like what you're saying is that the added spool up from a tighter primary isn't worth the lost of top end from a bigger housing? Because I'm still in the air about the t4 or t6 1.1, and trying to find a 1.32.
 
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gwhammy said:
Convertor selection means as much as turbo selection. I can build 30 of boost towing locked in overdrive. Going threw the gears it doesn't build this kind of boost as fast but my thinking is once locked everything is hot allowing for the extra boost. Moving off the line with the tight convertor I ease into it to avoid to much smoke. Of course all this has to do with the outside air temps and how hot the motor is. To just say it makes 30 lbs. of boost locked at 1500 is not a true statement.

The 01 with the 341 over 3b spools fast, not as fast as the hy35 single it replaced but fast. Probably 100 or more rpm's faster than the 351 I started with but the convertor is not as tight in it.

I don't have a pressure reading between stages but the 351 is gated at 26 give or take a lb. or two. With the 160 pump racked barrels and 5x.012 injectors it maxes out around 58 lbs. of boost. I would like more but it stays together this way and it is my main work truck.
Click to expand...

gwhammy said:
I need to say, 30 lbs. with a loaded trailer making the motor work. It varies but I've seen 30 a lot. I will usually back out of it or shift out of OD to not lug the motor this hard.
Click to expand...

I completely understand how load/heat effect since I've been playing with this as a single. In OD this 67 comes on about 1800, locked (OD on or off) it comes on about 1600-1650ish. This is rolling into from 1000rpm. If I'm already cruising at any psi besides zero, the spool in near instant.
 
JQmile said:
The 71 is k31 based (Aurora 5000) and I actually think it spools a little too quick...but the response seems very good once the rpms are up. For instance, if the truck makes a shift into OD and locks the converter at say half throttle, it drops all the way to 1,500rpm but the turbos are still making about 20psi. The engine pulls through it without any surging. I had originally planned to push these small chargers to see how much power I could make with them, and this thread is kind of renewing my interest in that. If I could make, say, 800rwhp or so with a 57/71 combo, I think it would freak a lot of people out...:Cheer:
Click to expand...

Thats another reason I'm flirting with a bigger housing on the 67, and maybe larger turbine. I'd love to do 700 with it in a twin set. It's not 800, but it'd still be cool. But who knows, maybe the 13mm p&b would get me there LOL
 
The 1.32AR housing is only available for the 88/96mm turbine wheel.
 
Smokem said:
The 1.32AR housing is only available for the 88/96mm turbine wheel.
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Thats what I figured, but I was holding out hope that there was one somewhere for an 83 LOL

So I guess just T4 or T6 1.1 is my only question now.
 
There is also a 1.25AR T6 housing for the 74/83mm turbine wheel.
 
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