The HOLSET Thread

If you want to keep costs down and already have the parts, yes your twin scroll turbo will work on a single scroll manifold. It just wont be as responsive as it potentially could be with a proper twin scroll manifold.

How big would the difference be against a twin scroll manifold? No idea
 
thebe said:
Thanks for the reply. Benrice explained the twin scroll/single gate differences spot on.

I have fitted separate breather can for the oil pan and another to the Cam covers. I dont think I should get much pressure in the bottom.. Surely I still have stock Pistons but with New rings. The oil pan breather is an10 fitted above oil level then T'd so that one hose goes to the side of the can in the top and the other flows back from the bottom of the baffled can. Breather filter at the top (now extended with a hose and behind the bumper in a dry spot).

Exhaust is 3,5 turboback with a short section a tiny bit smaller id (maybe 1cm or so) before the rear cannon. One straight through muffler in the middle with a cannon at the end. Ewg pipe (50mm diameter) joins the main exhaust after downpipe.
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Ok, sounds like a reasonably fresh engine then, is it still running stock valve springs though? What headgasket? Might be worth doing a hot compression test just to make sure it hasn't lifted the head after those initial 2bar pulls you mention. An HX35 on a 3L is going to be great for response and considering RB25/30's don't like to rev massive amounts it's a good fit IMO. The torque @ 23psi would be immense!!!

Mrodoc said:
I think its got confused - somewhere along the line or im just being a bit stupid -

So my 10cm housing is twin scroll and my manifold is single scroll -

I will get a picture tonight of the manifold to show you where it connects - i have been debating selling the manifold and using that money to get it look half presentable and then saving for a proper manifold from Sinco like you said -

you don't think someone would be willing to swap a HY35 for a HX35?

Im kind of in the mindset where i want to do things once and do them right, but i think getting my car roadworthy standard is going to be more important and just saving the £5k its going to cost to get the rest of my parts in - but also kind of tempted to run the engine till it blows and then build a 1.5jz 'Properly' if you know what i mean?
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I hear ya, doing it once and doing it right so you can make the most out of it for as long as possible is a good approach, but agree that the focusing on other areas so you can utilise it sooner is probably more important right now.

People tend to desire HY35's more than HX35's as HY35's perform better on single scroll manifolds, so it might be hard to do a straight swap. And if you would want to go down the route of a 1.5JZ in the future, keeping the HX35 and going twin scroll manifold (ie the Toyota version of what thebe has built) would be the better option. An HY35 + single scroll manifold (with the comparably more restrictive, single scroll turbine housing) isn't going to perform as well as an HX35 on a twin scroll manifold when you're fitting them to a bigger displacement engine, but they would perform almost identically on what you have right now.

Nothing stopping you advertising your single scroll manifold for sale, and if it sells then grab a twin scroll manifold and pay the difference. Can all be done while you concentrate on getting the rest of the car road ready :)
 
Yup completely freshened up engine. Maybe 250km's under the belt before dyno.

It has athena 4 layer metal headgasket with arp headbolts (conceptua tuning recommended far over cometic). Yes stock valve springs still. Could those be the issue? Im already at 23psi :/ seems strangely low numbers for this turbo and engine. Limited to 6800rpm
 
BenRice said:
I hear ya, doing it once and doing it right so you can make the most out of it for as long as possible is a good approach, but agree that the focusing on other areas so you can utilise it sooner is probably more important right now.

People tend to desire HY35's more than HX35's as HY35's perform better on single scroll manifolds, so it might be hard to do a straight swap. And if you would want to go down the route of a 1.5JZ in the future, keeping the HX35 and going twin scroll manifold (ie the Toyota version of what thebe has built) would be the better option. An HY35 + single scroll manifold (with the comparably more restrictive, single scroll turbine housing) isn't going to perform as well as an HX35 on a twin scroll manifold when you're fitting them to a bigger displacement engine, but they would perform almost identically on what you have right now.

Nothing stopping you advertising your single scroll manifold for sale, and if it sells then grab a twin scroll manifold and pay the difference. Can all be done while you concentrate on getting the rest of the car road ready :)
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I put the manifold up for sale yesterday and its already sold, i cant afford the difference at the moment so the money will go on a new front bumper and sorting out my wheels set up so it finally sits nice -

But yeah my plan would be 1.5jz and basically do as much as possible to future proof it for if i ever wanted to go stupid with a big T4 turbo -

I should really make a list of everything i need and start sourcing really,
then when im in a position to do it in a speedy ish time - then source the 1.5jz separately once i have somewhere to build it -

Just wondering, and this is probably going to be a stupid question, is it worth getting the turbo rebuilt even though there is no shaft play at all?
 
thebe said:
Yup completely freshened up engine. Maybe 250km's under the belt before dyno.

It has athena 4 layer metal headgasket with arp headbolts (conceptua tuning recommended far over cometic). Yes stock valve springs still. Could those be the issue? Im already at 23psi :/ seems strangely low numbers for this turbo and engine. Limited to 6800rpm
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Considering you're using an RB25DET head and stock valve springs, 23psi would more than likely be pushing the intake valves open on the compression stroke, meaning you'll be losing compression. Upgraded valve springs are not a big cost, and to be frank, they should have been factored in to the build if you were planning to run over 20psi. If it is the case, hopefully the valves haven't been pushed open so much that they've made contact with the piston.

If i was you i'd get a boroscope and check the piston's for any valve marks, and if there are none, proceed with upgrading the valve springs. Supertech make some for around US$150 that are proven to work well

Mrodoc said:
Just wondering, and this is probably going to be a stupid question, is it worth getting the turbo rebuilt even though there is no shaft play at all?
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Tbh, if you can find a reputable company to fit & balance a bigger billet compressor wheel with extended tips, and give the bearings a once over at the same time, then that wouldn't be a bad thing. But i would consider that a nice to have considering your situation.
 
@thebe - More boost with no more power usually means either a leak or head restriction.
My mates 8cm hx35 made 375@23psi on his SR20 but the guy he bought the exact same kit off had a printout from protuner for 411@17psi but he had 264 cams.
Holsets are proven to 35+psi so I can't see that it's running out of puff but can defo see your frustration man.
 
Thanks for the help guys. Yeah its a bit frustrating as its been in the garage for 2,5 years after the rb25 broke piston ring caps.

Anyway, I didnt change the valve springs because on sau forums people have had quite impressive results with stock head. Do you think the supertech single springs would be up to the task or would dual springs be needed? Ive heard jap brand springs are quite soft and not a good upgrade, true?

I'm using the stock bypass valve (due to people saying its goooood) and now after a few days digging it seems people have had leaking issues with them after 17psi or so... Now thinking its time for turbosmart bypass... Kompact (34mm) or the bigger universal (38mm) though? The bigger one is almost double the cost

On-topic: the holset is making cool noises and 12cm rear on the he351 (hx40) seems like a nice pair with 3 liter engine
 
I must have missed that you had the stock bypass valve. People tend to get good results out of the stock bypass valve if they crush them but if it is leaking then block it off or change it for a Turbosmart for sure. The Kompact will be enough
 
Mrodoc what was the quality like on that cx racing manifold did u test fit it. If so what was the fit like thinking of getting one thanks phil
 
I've bought a sinco t3 twin scroll for my 1jz non vvti been looking at turbo choice and I'm a bit confused. I'll be in a soarer daily automatic. I want it to be responsive and about 480 bhp. Would a hx35 10cm twin scroll be a good choice or an hx32 10ch twin scroll. Any advice welcome as I'm new to this game thanks phil
 
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HX32's are great for being responsive on 2 litre engines but if you're shooting for 480hp then HX35 all the way, especially with a 10cm twin scroll

That will sound horny af too, pity about the slushbox. Your torque converter might not be too happy with you after a while though
 
For 480 without cams I'd say you'd be better off with a 12cm hx35 if you're only gonna run 1.5 bar. Not gonna be a whole lot different than a 10 just a bit more up top.
Will be super responsive and good power with a 10cm anyway though
 
Yea thanks not to bothered about the top bhp to be honest would just like a nice responsive car and not laggy as it's my daily.
 
Hey guys

Im using a he351 on rb30/25. The turbo has a 4" induction and Im using 3" intake pipe. Can this effect the turbos performance? Currently running 1,6 bar, possibly more in future once I replace the leaking oem bov.

I have 4" -> 3" reducer right before turbo as Ive heard this way the maf is less likely to play games. Using 3" intake due to using hpx n1 maf and at my power goal 3" is ideal for the maf. MAF is placed right after air filter.
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Don't think it would have a huge effect man. It seems to be common practice when running an AFM. I prefer the map sensor for tuning and aesthetics but use what you've got
 
Thanks man.

The turbo is awesome btw. In 4th gear (no traction in 3rd on the road) over 1 bar of boost at about 3k rpm and 1,6 before 3,5k. Pulls hard to 6800 where my limiter is atm. Ran over 2 bar of boost when we were playing with boost controller at dyno so the 14cm rear doesnt seem to choke the 3 liter. Cant wait for next summer when I get my bypass and some other goodies fitted.
 
Great to hear dude. I've got a 9cm HE351 for my 1JZ so anything close to what you're getting would be awesome.
Still having issues with the stock BOV? Still the same power as before?
 
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