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GSX1400 engine Turbo project


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Posted (edited)

Guilty as (turbo)charged xD(although i had already mentioned that it wasn't due to go in a bike)

Dry sump would indeed be perfect, not for the budget though. It would 100% need total home R&D and fabrication, i doubt anyone provides such equipment for this engine

I'm hopeful that a sump baffle situation should be enough

Edited by Joseph
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  • 2 weeks later...

Looking at the sump i'm actually not sure that baffling is possible or even necessary ? The pick up is very deep low down and cased in, and based on the fact that the oil sump level is actually 2 inches above the oil sump mating surface, it might take quite some G force cornering to empty the oil out of the pickup area.

Anyways, not there yet, i'm currently looking at the header design.

I've seen many online, basically a 4 into 1 with a flange plate for the turbo to bolt onto.

Whats the general consensus on turbo headers ? NA engines need equal length tubes, some do tapered diameters etc, there's lots of potential in the header for those, but on a turbocharged setup how important is the header design ?

Asking because i have space issues that i don't want to dig into too much, so if a very compact header is ok, i'll take it from there.

Here is a photo of the header i had on that slabside :


Two pairs of 90 degree bends from cylinders 1 and 4 into the turbo flange, and 2 pieces of straight pipe tapped into that from cylinders 2 and 3.

Sounds alright ?

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Another question and doubt heavy post.

Right. So this is what i'll be working with :



HE221 as you can see. Good deal made with someone who'd bought all this stuff for his diesel Mercedes before figuring out that it would be too small for his appliance.

Looks like these Hoslets are the growing trend in good options for a 4 cylinder bike engine though.

Beyond the damning fact that now that i have a turbo in hand, i have no idea where it can actually fit on the tricycle i'm building... O.oxD

... I still need to dial it in.

It now springs to obviousness why external wastegates are in some (most ?) cases, a great idea.

My case potentially being one of them.

Current orientation of the turbo inlets/outlets will need drastically changing to suit my needs.

Is it correct to state that, as long as the bearing housing is horizontal (oil pathway therefore perfectly vertical), the turbine and compressor housing can point any which way i want ?


The vacuum unit setup and placement will then cause problems, because it is solidly bolted into the compressor, with the actuator rod of the vacuum unit set in a line towards the flapper.

If i can rotate the compressor outlet to wherever I'd rather it be, if i make an outboard vacuum unit mount taken off the chassis for example, in order to retain current unit position, I should be good to go ?

Thanks !

  • Like 1
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Yes, you can rotate both compressor and turbine housings as you like. What matters is the center section. You want to keep the shaft roughly horizontal and oil ports more or less vertical. I think I have seen +-30° from vertical recommendation for the oil ports somewhere.

And yes, you can mount the wastegate actuator wherever you like as long as the mounting is solid in relation to the turbine housing and the lever angles work. But here it's good to give some thought for practicalities like how you can install and adjust the actuator...

Regarding the header design. My opinion is that tube length matching isn't very critical on turbo headers. But what matters is the collector design. If possible the primary pipes should join at relatively shallow angle directing the exhaust pulses nicely into to the turbine inlet. And try to avoid too abrupt cross section changes there. Pipe diameter is a though question, I have seen both small and big pipes working pretty well. Again, I would try to avoid big steps in the diameter, from the head ports to primary tubes and from tubes to collector and turbine inlet.

  • Like 1
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Thanks for all that info.

Based on what you said (and what i can fit), if i build something similar to the photo i posted, it will be merging two 38s (from cyl 1 and 4) slightly stretched at the end to get to 51 with v band connector at the exit of the header, then a short length (around 45cm, can't do less) of 51 between the header and turbo.

After that it would be 63 from the exit of the turbo to the rest of the exhaust system.

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1 hour ago, Joseph said:

Based on what you said (and what i can fit), if i build something similar to the photo i posted, it will be merging two 38s (from cyl 1 and 4) slightly stretched at the end to get to 51 with v band connector at the exit of the header, then a short length (around 45cm, can't do less) of 51 between the header and turbo.

So 2 and 3 would join to 1 and 4 before the main collector? Ideally you should step up the pipe size after those merges to make it proper 4-2-1 system. I think the connector pipe between the collector and the turbo will hurt efficiency a bit but probably not too badly. Try to keep diameter of that pipe relatively small, not any bigger than the turbine inlet.

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Yes thats it, i have an idea to make a compact merger setup for a nicer integration of pipes 2 & 3, it adds work and complexity but it could work out ok.

Space is always the issue

Indeed having the turbo just after the manifold exit would be good but not possible here.

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  • 1 month later...

Right, i've been working on the header and turbo placement quite some, not many photos to illustrate my attempts but i should get a solid mock up soon

A few more questions while i'm at it

- this air and oil cooled engine will be encased in bodywork, so not much natural airflow going round it. 

I have planned more cooling capacity, and while i'm plumbing everything to get it up and running I'm thinking i could maybe fit a (small) oil cooler to the turbo drain line to add a bit of cooling to a hot line of the system ? 

Although i'd like a mechanical scavenge pump, for the time being i'm just going to use the classic Facet, maybe cooling the oil before it going through the pump would be good too

- Holset HE221 parts seem rare, i have no idea what to bolt onto the outlet of the compressor to link to the IC ? I ordered a Vband clamp and flange set and was planning on making a simple stainless intake pipe but the clamp doesn't fit, the flange diameters don't match, the Holset seems specific ?

Welding is possible but i think it is better to keep the compressor standard, it makes life easier for future maintenance

- had the oil feed banjo screw threaded to put a restrictor jet in, any suggestions as to what size jet to fit ? 



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Posted (edited)
On 5/23/2024 at 1:12 PM, Joseph said:

I have planned more cooling capacity, and while i'm plumbing everything to get it up and running I'm thinking i could maybe fit a (small) oil cooler to the turbo drain line to add a bit of cooling to a hot line of the system ? 

Although i'd like a mechanical scavenge pump, for the time being i'm just going to use the classic Facet, maybe cooling the oil before it going through the pump would be good too

Oil cooler on the oil return is a bad idea. Apart from space constraints, any restriction  will result in smoking. You could theoretically place it after the catch tank, but the amount of energy you will cool down this way is minor anyway: hardly any flow.  Better to use an as large as possible aftermarket cooler  and use quality oil which is replaced frequently. Thought while typing: you could add cooling ribs on the catch tank. Doesnt hurt but again flow is minimal so improvement is probably not noticeable.

 I never used a facet pump, what I read is that for some people it works fine, some have them fail frequently. Maybe there are chinesium variants around? I use a crank driven  mechanical pump, works nicely and not that expensive. For me its worth the money that such a key component is reliable. When scavenging, dont forget a breather above engine oil level on a catch tank to avoid vacuum.



Edited by peter1127
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Thanks for the very good explanations. Interesting point on the vent high up from the catch can, i don't remember that being mentioned before.

I think you're right, i may as well just go straight away for the mechanical pump, it's not like they're unavailable for these somewhat less go-to for tuboing engines.

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Posted (edited)

As you can't dry sump the engine Would your engine placement allow a "big wing" sump ala mk1/2 escort rally cars,  if the stock oil pan is suitable for modification , it would help prevent oil surge through corners and increase the oil capacity and thus cooling just an idea for you ....


Edited by DAZ
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Increasing oil capacity does seem like a good idea. Originally on the bike there is a 13 row oil cooler, I have a 14 row cooler/heater for the head and 2 19 row coolers for the front of the car, so that along with the extra plumbing has tripled the cooling capacity.

Not sure whether i can add wings to the sump due to space though, and how much i can pester my mate who welds alloy for me at his job, he's already needed to mod the IC i bought xD

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I'd be cautious about adding lots of smaller coolers against one larger one due to possible limitations of oil pump to have pressure capacity to push through multiple restrictive coolers and oil lines connecting them all up? As this is a car application, a 3 port scavenge / pressure pump, dry sump and remote tank would certainly be the best solution - plenty of Hayabusa's using dry sumps!

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Damn xD that is a good point

The Manual states that the nominal pressure of the oil system on these lumps should be between 45-85 PSI at 3000 rpm. Weird that there should be such a tolerance gap at a given engine speed ? But thats the figure.

Obviously since i literally have no idea what i'm doing, i have no idea how to work out whether thats good enough or not.

We have OC bikes on here running aftermarket 19 rows + head coolers, but i guess none with 2 mains + head.

Would any (if possible) swapping of oil pump gearing ratio be any good ? Or is it one of those more flow/less pressure things where you basically compromise (didn't i read something about AC GSX750 pump being fitted to AC 1100s for some improvement reason ?)

Dry sump is an ideal solution, yep, but thats a whole can of worms and budget i hadn't planned to cover (and currently again have no idea about how and if i can fit it on this).

Obviously if the choice is between dry sump or a broken engine, i'll have to sort something out O.o

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Of the 'normal' OC engines - GSXR, GSF etc. they have a two part pump, one does the pressurised lubrication system, the other does the cooling circuit. I think the broad range quoted covers both sides as generally they pump multiple gallons of oil per minute such that probably 50% is bled off straight back to the sump via relief valves - the HP side will hit 100psi when cold whilst the cooling side doesn't have much pressure but relies on flow and contact time to carry heat away. Hence my thinking that multiple rads adds resistance to flow which could result in worst cooling but increased capacity.

The OC's have fixed gearing unlike the AC bikes - non adjustable - AC variants done mainly for a boost in pressure - 10-12psi std, upto 20-30psi when re-geared.

A dry sump system has lots of advantages - massive (comparitively speaking) oil capacity, no oil surge / sloshing in a 4 wheel application, simple pump re-gearing to slow or speed up delivery / pressure, cooling circuit for oil tank can be independent of engine and taken to extremes, the engine can be mounted lower in chassis to improve CoG and handling due to shallow sump!

Its always an unknown with engine modification - will it hurt the engine, will it reduce reliability? Sometimes 'over kill' can work against the common good!

  • Like 2
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That does make sense. 

As it stands it's just going to be a rolling chassis for some time still so i can set it up as planned and gauge what pressure(s) i have. 

A mate mentioned running the main coolers in a parallel configuration to potentially reduce pressure loss, although that would be at the cost of lower flow ? Might help on the contact time aspect ?

Generally speaking are the oil lines going to the head on the high or low pressure circuit ?

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Did a little bodgery, i don't usually use files to make stuff cause i'm a lazy git

So these lumps have a PAIR system :


Obviously who cares about that, so i took the caps and went to town :





Result : the oil catch tank

Does that pass inspection @peter1127?


  • Like 2
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I seem to be having trouble working out how to actually assemble the header. I have literally never done anything like this before.

I've figured what I need in terms of bends and tubes etc, and also the kit that i want to make out of all of the bits, but i'm hitting several walls and it seems that i'm not going the right way (I often don't see the easiest route)

I've had spigots and plates made in stainless :


My plan was to insert my 4 bends cut to suit into these, bolted to the head, and tack the bends together.

So i did that and then it all went to shit because when it comes to just tacking the spigots and tube ends together (from inside the tube, like many headers are made from what i can see)

It goes all sideways, and can no longer be fitted to the head.

I was thinking that using the head as a jig was the general approach ? 

I also tacked a bridge over the 4 tubes but that didn't help to prevent them going all over the place 


Should i tack the spigots on the pre-cut-to-length bends ? But that seems like it'll distort the bends anyway ? 

I obviously need to start all over again, but at least i have a model.

Also not the easiest to cut bends straight down and equally with no tools xDalthough i didn't do too badly

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Why tack the spigots - they aren't going to ever be anywhere other than the end of the pipe so fully weld them, then tackle welding pipes to collector - at least the spigots & runners can be bolted in to head, tight, to prevent excessive movement. Yes, pipe can move when finish welding but tacks are unlikely to kink out of place. Once all tacked up and held into head and into turbo (which should be well constrained) the easily accessible joints can be finished TIG'd to make rigid manifold, then removed from fixture to finish welding the remainder not welded first time!

You are aware the pipework plan chosen isn't going to perform the best?  Flows are conflicted and the 90 deg turn into the Vee band clamp section isn't good. I'm all for DIY turbo builds but bad design leads to poor performance and disappointment ! Just saying!

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Thanks for your helpful insight.

Many of your questions can be answered by the following :

I don't really know what i'm doing, i've never built exhaust bits before, and it's all tacked because i don't know how to weld so my mate is going to TIG weld for me what i pin together.

I was trying to make some sort of a merger system, and also, i'm really limited in space, if i want to preserve passenger footwell i'm limited in manifold efficiency. (Turbo has been remotely mounted for example, no choice)

As a result i can't buy an off the shelf expensive but guaranteed kit either.

I think i'm just going to copy the one that i pictured earlier in this topic that Dave made for the Ol'Red slabbie, seems the easiest and most compact even if not the best design.

As far as performance goes, this is now thanks to my mods more or less a super big bore 1402cc Bandit engine, if i ever reached the usual 240-250hp that turbo bandits seem to claim, that would translate to a car with a power to weight ratio of 600-625hp/ton. I was projecting getting to the symbolic 500 (same as the Veyron) that would be the 200 hp mark, tbh anything around that would be satisfying enough for a car i've entirely designed and made myself (except real welding and lathe work xD)

Pic of the intake side since this has been a long rant :



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As gixer1460 said, but to add: (to save disappointment) when you use a head as a jig for tacking up/partly welding your headers when you have figured out your design. Weld as much as you can and if possible, back purge your welds but also very important and if space allows-try and weld the whole lot whilst in the jig or make one that you can get all the way around. Stainless pulls like a bastard, especially if the fit-up isn't great. You may find you weld most of it fine then take it off to weld fully only to find its pulled and doesn't fit your ports properly anymore. Not fun and a ball ache to sort out.

Best of luck. It's not easy.


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I keep forgetting this is a damn 4 wheeler! From pics I guess some space could be generated for better manifold AND turbo placement if the engine was rotated backwards towards the intake (which would rotate down). Ltwt. weight is good but not at the expense of a rigid chassis - i'm not seeing much triangulation going on and the chassis rails look 'skinny' ie. not much depth to them? When you look at bike installs, they are, and have to be compact, to avoid frame down tubes and a moving front wheel and i'd say most would fit in a slightly enlarged space happily. You probably have more space than you realise with a bit of re-jigging!

If you are aiming for 500hp/tonne/1000kg that translates to about 500kg @ 250hp, all up weight which is bloody light for anything with 4 wheels, suspension, seats & bodywork!

Some examples of compact pipework - you don't have to follow them but good inspiration - the NLR example is a very good, free flowing manifold that helps a Busa engine to over 500hp from 1300cc! The vee band flange is for wastegate and best placed for control.



NLR pipe1.jpg

NLR pipe3.jpg


  • Like 2
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Ah i should have excavated google images a bit more before starting this item xD

Number one you put and the NLR seem doable (first one especially) and it may be that the header wouldn't stick out in the way too much, especially if i make those head exit/spigot pipe straight sections slightly shorter

I did consider tilting the engine but then I ended up not doing it for some reason. As it stands i still could but that means a lot of work that i'm not sure i'll find the motivation to accomplish.

Four ? It's actually a 3 wheeler xD so no chassis torsion to speak of, compared to a 4 wheeler, on this type of structure.

Stock factory weight of the standard car all filled up is 375kg. I'm guessing 400kg final weight is realistic with all the stuff added (rollcage, bigger diff etc) but i'll get it weighed when it's finished.

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