Inlet hose - turbo

Alex(Tenerife)

Alex(Tenerife)

True Classic
So I have been thinking about replacing my inlet hose, between AFM and turbo, for a couple of reasons. First is to allow me to move the AFM a little so the air filter can be in a better position and second to tidy the crank case vent/ catch can set up I have.
As a reminder this is on my UT engine in the back of my X.

Option 1 is a combination of universal silicone hoses with a slowly reducing ID. The AFM is 57mm and the turbo is a 45mm input. I was thinking 51mm in the middle for dump valve and crank case vent hose.

Option 2 is to buy a silicone replacement hose, designed to replace stock and then I can modify that to the shape I want. This would give a neater/simpler solution (also cheaper) but all of the ones I have found seem to jump down from 57mm to 45mm.
An example from ebay
They also are of unknown build quality as they are from China.

Ignoring for a moment the unknown quality and coming from China, is a single larger step down better or worse than 2 gradual steps down in diameter?
While I am doing this I want to minimise the turbulence in the air flow.

Anyone got any thoughts/experience with air intakes into turbos? I appreciate this is not the stock X1/9 type of question but I know there are a lot of you guys with more automotive knowledge and experience and I have.
 
I would just run a continuous diameter hose and put a reducer inside at the turbo to minimize the number of joints, difficulty of sourcing items in the future and so on. The turbo won’t care if there is a minor bit of turbulence at the mouth of it. The reducer could even have some radiused lead in to ease the transition.

That is how I would do it, but I am a lazy man.
 
ASH who I use for hoses out of choice do a 90 bend 45 to 51mm and another at 51 to 57mm, or a 45mm to 60mm in one go. But I think 60 is a bit too big for the AFM, which is why went via 51mm.

An all in 1 pipe with fewer joints is has fewer points of failure and is significantly cheaper.

Thus the dilemma
 
I agree that the reduction can be done right at the turbo. The reduction shape will act slightly like a "bellmouth" for the turbo inlet. Then use the same size pipe from that reducer as the AFM. You should be able to find a silicone hose with the two dimensions you need for the two ends, and any bends you desire....there's a ton of sources for this universal stuff.

Here is my UT turbo on a X1/9 engine. This was just a quick mockup. In my case the UT turbo and exhaust manifold is about all that is utilized from the original UT system. With a aftermarket (standalone) ECU the turbo inlet connects to the air filter (toward the left of this pic). But the silicone connector shown here (arrow) is what I'm illustrating.

029 - Copy.JPG
 
Thanks that looks good. Is that a 57 to 45 reducer?
Also wastegate valve looks interesting, is it one where you can change the spring? Certainly not stock :)
 
I removed my pipes from the Turbo inlet and replaced it with a flexi hose (made for this purpose). So much easier to place the air filter exactly where I want it now. I don't remember if a reducer was necessary to fit the TD04 14T but I will have a look if you need this info. Also, I didn't use the alu cones on the picture. I have a MaxxECU so no AFM etc, so maybe this isn't applicable on your car.
No power loss at all with this setup.
Img_2024_02_16_22_46_58.jpeg
 
Alex(Tenerife) said:
Thanks that looks good. Is that a 57 to 45 reducer?
Also wastegate valve looks interesting, is it one where you can change the spring? Certainly not stock :)
Click to expand...
I did not remember the diameters of that silicone hose adaptor but I was able to find the order information (bought it on eBay). The turbo inlet is the same as yours (this is a stock UT turbo), so that end of the hose is 45mm. But in my case the other end goes through the aluminum pipe you can see in the pic to a large aftermarket "cone" style air filter. Therefore that end of the silicone coupler is 76mm to match that pipe. With the huge assortment of pipe and silicone coupler choices available you can make anything you want easily by just piecing them together. Be sure to use T-band style clamps on ALL of your connections.

Yes, the waste gate actuator is a aftermarket item. They are a universal type product so you need to do a little fabrication to mount it in place of the original one. I used the stock mounting bracket and made some adjustments to it. It was offered with a choice of pull rod styles and a selection of pressure springs. Changing the spring determines its max boost level. A boost controller (I have a MAC valve that will be controlled by the ECU) adjusts it from there. It was easy to do and should be fun to play with once I finally get the whole build done.

I did similar with the blow off valve, a aftermarket adjustable item. These changes together with some mild porting (clean up and port matching) of the turbo and exhaust manifold should allow it run plenty of boost for my application. But more importantly I hope the changes provide a very reliable control of boost to prevent damage.
 
Hey Alex, since we are discussing the turbo inlet hose I'd like to make a comment about the rest of the UT's turbo piping. Correct me if I'm wrong (it's been awhile since I looked at this) but I seem to recall that all of the factory UT piping is undersized. By that I mean it is actually smaller diameter than the intake manifold's inlet ID. This makes all the plumbing a bit of a restriction for air flow. I'm sure it's fine for a bone stock engine/turbo setup used conservatively under "normal" conditions, but having larger diameter plumbing (at least matching the intake manifold diameter) throughout the full system would be a benefit. Especially if you intend to do any upgrades on things (and particularly if you up the stock turbo's boost a little by altering the wastegate actuator). This "undersized" attribute also applies to the stock intercooler; a larger and less restrictive one would be a definite benefit - even on a bone stock setup. That will not only reduce the restriction but it will cool the inlet charge temperature more. By reducing restriction (which creates higher intake charge temperature significantly) and adding improved cooling, it will increase the engine's longevity and reliability....in addition to potential performance increases. Therefore while you are redesigning the inlet piping maybe also consider upgrading all of it. Just food for thought. :)
 
Dr Jeff, all of my pipework after the turbo has already been replaced with stainless steel pipework designed. I'll try and take a photo of it next time I go to it if you are interested. I have a pipe same diameter as the turbo outlet to a large (maybe too large) chargecooler. I think the chargecooler has 76mm (3 inch) inlet and outlets. I then match the OD of the plenum, which is 63mm.
I believe the real bottlenneck here is the butterfly on the plenum. I have seen someone who cut and welded a larger butterfly in but I am not at that stage yet.
If I am after more power then I know I need to look at fuel rather than air. Stock ECU is my limiting factor. My goal here is to both tidy up the engine bay a little, my oil catch can is in the rear boot and to better position the AFM and air filter so its nearer the left hand air vent/scoop
 
Bjorn Nilson said:
I removed my pipes from the Turbo inlet and replaced it with a flexi hose (made for this purpose). So much easier to place the air filter exactly where I want it now. I don't remember if a reducer was necessary to fit the TD04 14T but I will have a look if you need this info. Also, I didn't use the alu cones on the picture. I have a MaxxECU so no AFM etc, so maybe this isn't applicable on your car.
No power loss at all with this setup.
View attachment 81637
Click to expand...
Sadly still with the stock ECU I can't take this route.
 
Alex(Tenerife) said:
Dr Jeff, all of my pipework after the turbo has already been replaced with stainless steel pipework designed. I'll try and take a photo of it next time I go to it if you are interested. I have a pipe same diameter as the turbo outlet to a large (maybe too large) chargecooler. I think the chargecooler has 76mm (3 inch) inlet and outlets. I then match the OD of the plenum, which is 63mm.
I believe the real bottlenneck here is the butterfly on the plenum. I have seen someone who cut and welded a larger butterfly in but I am not at that stage yet.
If I am after more power then I know I need to look at fuel rather than air. Stock ECU is my limiting factor. My goal here is to both tidy up the engine bay a little, my oil catch can is in the rear boot and to better position the AFM and air filter so its nearer the left hand air vent/scoop
Click to expand...
Excellent. ;) I wasn't aware of all your existing upgrades (or I'd forgotten if you told me before :rolleyes: ).

My intercooler is a bit too big as well. But I wanted a very specific design to be able to locate it how I desired. And at the time it was a choice of this bigger one or one that was a little too small (in my opinion, although it was still bigger than the stock one). The only potential downside to using a oversized intercooler is it may induce a small amount of turbo lag if its internal capacity is huge. However it will also offer more temperature reduction and reduced restriction, so it will perform better at higher boost or engine demand. Considering the UT turbo is very small, it has zero lag to begin with. So I feel the potential of a slight amount of lag is more than offset by the potential benefits. Especially in terms of added reliability and dependability. Mine is strictly a street build (not track), and my goal is not ultimate performance but enhanced drivability (especially since I must retain the AC where I live). Therefore its a relatively conservative build with everything aimed at allowing the stock 1500 (X1/9 SOHC) engine to survive.
 
I agree, the butterfly is the biggest restriction in the intake tract. But I also think the head is as big of a restriction (if not more) overall. Going to a much larger butterfly won't help if the head isn't capable of flowing enough to benefit from it. Some porting can benefit the head a little but the real problem is the antiquated design of the head itself; counter flow, two valve per cylinder, single overhead cam, etc. Some testing would need to be done to see just how much the flow rates were affected by making various changes like a larger butterfly. But my guess is a mild increase in the butterfly should help some. The Mk1 UT's butterfly is the same size as on the 1500 X1/9. Isn't the butterfly larger on the Mk2 UT or Punto Turbo? Interestingly there's a intake manifold from a Strada (?? I think) with a larger butterfly. And it will bolt onto the X engine. However it also has some large water cooling jackets cast into it that are obtrusive (and might even interfere with the turbo's exhaust system?). Otherwise it would take a lot of modification to change the butterfly on a stock manifold. Someone here (can't recall who) did that by removing the stock neck and welding a different butterfly assembly onto the end of the 'log'....

20170527_115928 - Copy.jpg


But keep in mind the original UT's turbo is a very old design and very small. If you start going to a larger butterfly along with all of the other improvements (including a standalone ECU), then really the turbo itself would need to be changed to a modern design. At which point the head becomes a HUGE problem. Trying to force all that boost through its very restrictive design will create exponential thermal increases, resulting in detonation and engine failure. At that point the REAL answer is finding a complete modern engine designed for high boost. :D
 
A bigger Throttle Body will probably add a few hp but a bigger TB is absolutely useless if not having a modern ECU and thereby removing the very restrictive AFM. I agree with Jeff, the most flow restriction is in the head. The tiny stock IHI Turbo is another limit to reach +160 hp and will not produce more power with a bigger TB. As discussed previously, heat is the biggest enemy and therefore a good IC is necessary. IMO a water to air solution is the best solution on mid engine cars but that's a separate discussion.
The bottom on X1/9 and UT Mk1 is very strong, even better than most modern engines and handles 250 hp with stock internals (UT). Unfortunately the open deck bottom on UT MK2/Punto GT is quite weak and tends to crack.
I've heard that high flow 16V Dallara head copies are available from Italy, but they are very expensive. They fit more or less bolt on I assume. It is a pitty that China haven't picked up this business opportunity.
 
My goal with my car is to have an of the era modified car. Kind of imagine what it could have been had fiat been so inclined.
I know ECU and bigger injectors is my next step and I kind of don't mind that even though its very modern.
More info for you guys by engine was rebuilt by Guy Croft about 11-12 years ago and with a goal of it being a strong engine for road use. His main concern was actually how to fuel the massive amount of air that the engine could now take. (His words, as far as I can remember them)

This thread has gone off topic a bit :) My turbo makes a nice 1.1 bar until about 4k rpm then it starts to drop as the turbo can't keep up, but for road use its time to change gear anyway. So for now I am happy with the turbo. maybe after the ECU and injectors I might go for a hybrid, but probably not.

Thanks for all the feedback you guys gave, after your thought on inlets and a bit of reading about bell housings I might make up a stainless inlet
with the main body being 57mm only reducing down right next to the turbo inlet. I just need to take a look and see if I have physical space for it where I want it to go. Time for a cardboard mock up I think.

I would have used a silicone hose solution but its going to end up costing a very similar amount, if not more to get all the hose fittings as I want them.
 
Alex(Tenerife) said:
If you fancy checking out a long article I found this which shows opening up the plenum. Notice how he used a mk1 UT plenum rather than the mk2. I understand the mk1 is a better start place.
https://www.fiatforum.com/threads/uno-turbo-build-thread.483268/
As I said I probably won't do this but its interesting.
Click to expand...
Nice build. I wish I had that alu welding skills.
I also think the Mk1 plenum is a better start place and it looks better as well. I like the way he made the intake runners to accept modern injectors and a straight fuel rail. I did it another way that you can see in the Turbo Thread. My 1.5l is going in in my 128SL and am going to inject it. I have a injected plenum on the shelf but no fuel rail so I will have a closer look at this mod.
Here is another TB mod from a Fiat 600 with UT engine that I noticed on an Italian car meeting in south of Sweden 2022.
IMG_20220501_111035.jpg
 
Another choice would be the Yugo GVX Motronic intake which uses a straight line fuel rail but has the throttle body at the far end by the right side strut tower. Sawing the opening off and welding it to the other end would get to a better situation. It was for a 1300 so hard to say what the passage openings would be.
 
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