HX25 Turbo?

[jt15833]

I'm waiting on this turbo to arrive and want to here what you think of it. It's going on my CA .

I haven't seen very much on this turbo at all. I know the hx35's are more common, and hear about them being used on KA's and RB's (even 20's) so I figured the HX25 should be a responsive, semi-powerful turbo.

This is some of the stuff I have come up with from research. I'm going to use it either way most likely but I wouldn't mind getting some input / predictions as far as responsiveness, and the best way I could run this turbo.

First and foremost, here is the light spec sheet from http://www.holset.co.uk

Flow rate is listed as 0.23 Kg/s. Ok, well how useful is this number without knowing what it means? I found a thread a while ago about calculating engine flow rates and using it to determine how good a turbo is based off it's compressors map. Here is the excel sheet I used to calculate airflow at different RPM's. Volumetric efficiency is assumed at 90%. Max boost is also assumed 14.7 psi to give an easy pressure ratio of 2.0. Excel sheet is from Def on bimmerforums.com.



Holset provided me with a compressor map to look at which was a big lead. I used a line technique that Def described, and this is what I came up with. It's assumed to be 0 boost (1.0 p/r) at 2000 rpm and 14.7 boost (2.0 p/r) at 3200 rpm. 2000 / 3200 rpm are also the two points used for the green line.

This is really the only thing I have to go off to see if this turbo is good for my engine. I'm still a bit unclear on how to tell though. The red line is on the map for quite a bit but comes off near the end. The end of the line is at 7500 rpm though, which is a bit high and ok if it's off the map. The green line represents a lower boost level, and stays on the map for a little bit more of its RPM range.

I wouldn't run over 15-17 psi so it's either of these lines I would be using, or a lower one.

This is the bare map provided by holset.

Here are the pictures of the turbo. Turbine housing looks to be pretty small, and compressor housing looks to be a good size.



Any input you guys have is appreciated! I will most likely be running Nistune for engine management, and 550 injectors. Engine is stock but has had everything replaced such as HG, timing belt, pumps, gaskets etc. Right now it pulls pretty hard on the stock turbo.
Modified by jt15833 at 2:13 PM 1/12/2008

[Reno]

HX35 Ca18det

Quote from iXer Super Moderator: "He used Nissan Sunny GTi cams and a HX35 with 16 cm² turbine housing. With only 0.3 bar boost it has more get-up-and-go than a BPU-enhanced S13 @ 1 bar. The boost threshold seems to be at 2500-3000 rpm, and can be improved upon as he had no boost control. It's put into storage for the winter now so I don't have any more data on it."

Personally i don't like anything lower than a 35 :P

heres more info on it i Believe... don't quote me on that http://www.vems.hu/wiki/index....issan

Matti Juntunens Nissan 200SX S13 "Diesel-Doris"



Status

Engine has been started up, but no tuning has been done yet.

VEMS Genboard specification

1-wire interface: Noignition driver: 4+4 as described on VehicleFitment/NissanCOPsKnock and EGT: Knock and 2 EGTLCD and PS2: YesMAP connection: 400 kPa on-board (5/3 mm pneumatic)mounting-style: no screwsPowerFlyback?: Noprimary_trigger: Hallsecondary_trigger: Hall

Engine specification

* Nissan CA18DET, 1.8 litre 4 cyl * Custom exhaust manifold * Custom intake manifold * H-beam rods and Wiseco pistons * Upgraded oil cooling system * Turbo is Holset HX35, 54/60 in/out * 440 cc low-Z injectors * Stock COP ignition system * Uses 24-1 trigger wheel as described here : VehicleFitment/Nissan

We have our first CA18DET running on the 24+1 trigger disk, with very goode results:



The owner reported back from his first track test that the engine was strong and responsive throughout the rev range.

We have used the standard wiring loom, COPs etc via the use of a harness adaptor:

[jt15833]

*wow* that thing looks nice. wonder what radiator that is, looks underpowered, maybe not though.

that is very cool but with my engine how it is i wouldn't feel safe with that much power. what i'm hoping for out of the hx25 is something very responsive yet a step up from an sr t25.

[Reno]

gotcha bro i believe it t3 flanged unless i missed something :P

LOL anything is better than the Ca T25

[jt15833]

The guy I'm buying it from measured and its same as t25 flange which is nice. I'd love do it to bolt up to the stock manifold. It's got a vband style exhaust which I am looking forward too.

Kind of off topic, i looked around and is 300hp (wheel?) the general suggested value a stock block can take before upgraded internals should be replaced?

[Reno]

correct, If i recall correctly Dee a.k.a Boost Boy had about 450 stock internals in his..

but yes if you want it reliable i heard all was needed was a head gasket? don't remember.... I want a CA

[Reno]

Anybody else have any imputs?

[Reno]

[jt15833]

dunno if my pics can beat that

anyway it came in today. I've had my ca18det stock turbo off before but never really noted the size. This thing looks pretty small though.

One of the best things I can do for comparison was compare the hx25 compressor map to other turbo's with proven results, gt25's and such. I also tried to compare the flow rates.

For example, the GT2554R's compressor map's max flow is around 28 lb/min where as the HX25 stops around 30.4 lb/min ( 0.23 kg/s). Just going off that, what kind of assumptions can i make for this turbo? Definitely better than stock turbo i'm assuming.

Heres some pics



if I clock this, I'm assuming I need to mod the wastegate actuator?

[Reno]

Very nice pics hmm that my be a well choice for the ca instead of a sr turbo :0

[Reno]

Bump For Updates?

[r34 gtr]

Looks pretty slick! Smaller than the 'ol S15 Spec-R, but not by much.

[float_6969]

actually the S15 spec r T28 is rated to the same flow rate, so they should make similar HP, 270-ish to the wheels.

[jt15833]

its for sale if anyone wants. very good condition and def. a stout turbo.$250 shipped takes it

[float_6969]

What? Now you're selling it? Why?

[jt15833]

eh I scrapped the CA a few months ago. Selling everything of mine 240/turbo related.