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Discussion Starter #1 (Edited)
I had previously installed a 12cm turbine housing on the H1C and was pleased with the results, but the itch started again. I wanted to up the ante a little more and decided to try out the Borg Warner 171270. There's only a few reports of this turbo, but the few who have tried it seem to be pleased with the results. I'd like to stay with a twin scroll, non-WG design because I don't want to change my manifold and down pipe combo just yet.

I ordered one up and what came in the box is a Holset 3522900, in the H1C family. From my research it seems this is correct, as the turbo was a joint venture between BW and Holset.

The only thing I'm confused about it is that it has a 16cm turbine housing, and I was expecting something tighter than that. I'm going to install it here in the next couple days, but I'm beginning to ask myself if I should go ahead and put the 12cm housing on it.

Anyone have any insights about these turbos?
 

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If you are dealing with a 4bt, a bigger turbo or any turbo in the H1C family isn't the answer. One of the HX30W turbos with a properly tuned injection system and timing can easily pass 200 HP. Might get 250 HP before you have to think twins. They will boost quicker and have lower EGT. The biggest single recommended would be the Super HX30W with a 46mm inducer and a 6cm turbine housing. Next best would be the 44mm. There is also a 42mm and a 40mm. All these turbos have the standard T3 exhaust flange. All except the Super have 3" air inlet. The Super is 4".
 

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Discussion Starter #3
Well I put it together, baby-H1C/12cm turbine housing. Its really quite peppy, boost comes on quick and strong. Feels like I lost a little on the top end compared to the big-H1C/12cm (worn out pig). I'm tempted to change it to the 16cm for that freeway feel, but I think it's good. Burns clean, never cracked 1000 deg. Seeing 20-21psi. I'm sure I could crank up the fuel a bit but I like smooth and economical. Fits the bill for now.

I'm wanting to see what I can do with a non-wg twin scroll setup anything else would require major manifold/downpipe changes and don't feel like fabricating right now. Maybe next season.
 

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If you're getting 20-21 psi boost I don't think I'd change it. Most H1C's with the larger turbine housing have a hard time doing much more than 15 psi. The HX30W I mentioned can easily do 30+ psi. The larger H1C is a top end turbo but suffers a lot at lower rpm.
 

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Any update on your turbo swap?

I have been running this turbo for 6 months and initially I had some issues with high EGT's and low boost; but that was my fault.

I am really liking this turbo, boost comes on linear and smooth with very little lag. I was thinking that I would regret not going with a super hx30w, but that would take considerable modification.

From my experience, this is a decent upgrade to the H1C.
 

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Any update on your turbo swap?

I have been running this turbo for 6 months and initially I had some issues with high EGT's and low boost; but that was my fault.

I am really liking this turbo, boost comes on linear and smooth with very little lag. I was thinking that I would regret not going with a super hx30w, but that would take considerable modification.

From my experience, this is a decent upgrade to the H1C.
Your running the Borg Warner (with what exhaust housing )? Or are you running the H1C with a 12mm exhaust?
 
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