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Hi all, new here. I have an MX-5 I want to do a K24 swap on. There are a couple of things I'd like to do different, because I already have a 1.8 with M45 supercharger (around 205 Bhp at the wheels). Just swapping a K24 with ~200bhp for the 1.8 S/C is nto much point (I'll lose a couple of kgs in weight, but won't gain much in power or torques).

I have read most there is, also on the Kmiata stuff (wow, those guys are good! (with the price-tag to go along with it)). And am keen to go for 300+BhP on my K-conversion. Yes, I know that means I will need the E46 6-speed with all the extra cost/effort that entails.

My idea to reach the 300bhp cheaply is also a supercharger (I just love the low-end grunt it can provide, and the 'whine' when it's doing some really hard work).

MercRacing do a kit, but at the best part of $5000 it'll push my budget for all the conversions to way over what the car is worth. Their kit is based on the TVS 1320 supercharger, so I started looking at a conversion similar to what I did with the M45 (from a Mercedes SLK). I found that the Audi V6 TFSI uses the TVS-1320 supercharger in their car, it comes packages with a drive-by-wire throttle-body and a bypass valve right in the construction. It also comes with an intercooler and a V6 inlet manifold (part of it), which is not so great. (Sorry the text is in dutch)



It's got a couple of great things going for it:
1. It's got a 90 degree bend at the end of the manifold. Great because space is already at a premium in an MX-5.
2. It's got an in-built air/water intercooler. Again, space-saving.
3. It has a bypass valve built in, which is also a great space-saver.

Couple of problems though:
1. It's a design for a V6. What are you thinking!
2. It's massive, much bigger than I expected!
3. It's drive-by-wire and the by-pass is also adjust-by-wire
4. Due to the orientation I'm choosing, the 90 degree bend is going straight into the bonnet.

Great thing is, I already have a plan for mating it to the engine, I would have to design/build a manifold that would take the 6 channels, and through a plenum, make them 'compatible' with the K24. It would sit at an angle, so as not to go above the level of the K24. The great thing is, I do not need the space for 'runners' because I am doing forced induction.I'll mock up a picture soon, just need to take a picture of the supercharger end-on and get the scale right.

Some questions (maybe you know the answers!):
1. These cheap pistons on ebay (low compression) are they any good?
2. Is there anything I need to be aware of in the K24A3 engine that is 'weak' or 'bad'?
3. The Throttle body for the Audi is a fly-by-wire jobby, anyone have any idea if KPro supports this? Or will I need to build something to 'convert this?
4. The bypass valve is a simple DC motor with a variable resistor feedack, will KPro be able to do this?

Thanks guys!
 

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Discussion Starter #2
Looks like it might work, although it could be a bit tight:


Hope the distance is big enough for:
1. The plenum I have to build,
2. The injectors and fuel rail.


It could be a bit tight at the firewall:


I have some ideas for the Drive-by-wire and the supercharger by-pass manifold: DBWX2 Drive By Wire Controller (Together with a Megsquirt III) should all work, I hope. Have downloaded the Audi information system (52Gbytes) to hopefully be able to get the correct plugs for the fly-by-wire throttles.

Lot's more to figure out, but no no-starters yet.
 

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Discussion Starter #3
Quite a lot of space too, maybe it's enough... Maybe not?


One of the manifold ports, showing the intercooler:
 

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Discussion Starter #4
Ah, going to have some problems with the throttle body in that position. This is a picture of the 'flat' water-block on the Kmiata set:


As you can see, it's made for a RWD applciation of the K24, to keep it as flat as possible. Could be a problem with the inlet manifold on the supercharger, it might protrude to far back. :-(
Maybe I can turn it 1/4 turn to make it fit, or make a 90 degree bend and then the throttle body.
 

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Very cool project. Any updates on the supercharger fitment?

Is that your engine bay above? Or just a reference pic from someone else?
 

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Discussion Starter #6 (Edited)
The engine bay is a K24 in an mx-5 engine bay, just a 'random' one off the internet.

I've had another look at the stock intake manifold and have discovered it has two parts to it. A shorter part to mount the injectors and the runners. I'll be cutting that up and try to weld some aluminium plate to the surface of it. This will result in a surface I can then weld the plenum to. The plenum will be sheet aluminium and should be strong enough to hold the supercharger.

I've ordered a water pump block off plate because I have to do a P/S water pump delete due to the space needed for the supercharger.

I've also ordered a BMW electric water pump. I have checked, my computer will be able to control it's speed using PWM.

I'm also looking into the drive-by-wire situation, I might just have to build something myself to get the Audi throttle bodies to work with my ME221 computer. I also need to think about the accelerator situation. There are some manufacturers who have a cable operated potentiometer. Just need to find out how/where to get one.

I also will need to get plugs for the bmw water pump, the Audi throttle body, the Audi waste gate, the Audi pressure sensors and the throttle cable potentiometer.

We are not going at light speed, at the moment the list of things to do is just getting longer.

I have also ordered a roll over bar and wilwood brakes for the mx-5, to be able to make it safe at these power levels.

I will also need some wider tyres, maybe a 225 section to get some more grip, to be able to put this power down to the road.
 

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I'm curious how you are going to effectively redistribute the air flow evenly from the 6-runner plenum to the 4 runner intakes.

I also used the 2-part TSX intake - runners (removed all the water jacket castings) & modded the plenum to tuck under the runners due to the space limitations in my mid engine Fiat setup. I also like the TSX PCV system integrated into the runners, it is very similar to the setup on my Volvo - it works.
 

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Discussion Starter #8
I have two theories:
1. To create a plenum myself, so a space between the supercharger outlet and the engine inlet, it will be a relatively shallow space, the 3 'slots' are about the same length as the inlet manifold, not quite, but close.
2. To cut the three slots into one big 'sleuf' or slot, basically making the supercharger housing itself into the plenum.

The second option would save space, but how would I connect the other three runners from the supercharger (V6, remember)? I could block them off, but I would lose cooling capacity in the intercooler.

If I use option 1, I could weld the plenum big enough to take in the second set of outputs too.

I could do option 2 first, and if the intercooler capacity is too small, go to option 1.
 

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Discussion Starter #9
This is kind of the problem that I have:


I feel I do need a plenum to make this happen, it will not flow nicely if I just 'connect them together'. I will probably need to open up the three openings into a 'slot' to make the air flow more freely.
 

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Are there only three openings? What about the other bank? Isn't there another flange for the other 3 cylinders? Trying to get the whole picture...
 

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Discussion Starter #12
Cut the inlet manifold today so I could test-fit the supercharger closer to the head. It's all goin to be pretty close. I don't know how much space there is in the car (don't have an 'empty' car for fitting):



It's all pretty close, this is the distance to the electric water pump plate from Counterclockwise rotation:



Here is the distance tot the starter:

Also not huge amounts of space!

This is the distance between the starter and the electric water pump plate (you are looking from the bottom to the top. At the top you can just see a supercharger port, and the middle of the picture is the inlet manifold (furthest from the camera):



Currently, I'm realising it's very close here, and even 'closer' in the car (If I ever do it).
My plan for creating the 'plenum' is as follows:
Cut slots in the supercharger, so the six seperate openings actually become two large openings, making it flow more freely and using more of the intercooler:


Then using two tubes (for better flow and easy of construction) to connect the two 'slots' from the supercharger with the inlet manifold (i've drawn it from two different directions, to get it cleared (because it looks quite complex). The red round bits are tubes with one side flattened off, this is the mating face for the supercharger. The round bit will be welded 'into' the inlet manifold to allow me to use it as a pivot, before I finally weld it. The connection tube will be quite complex, because it will have to miss the kocht sensor and the starter. It will not have to 'miss' the water pipe, because that will actually have to come out the front, not pointing twards the rear (RWD application).


From the side it makes even less sense. But it comes down to the fact that I think a flattened tube is an 'easy' way to mount a closed vessel to the supercharger.


I'll have to start by finding some suitable aluminium tube and then also finding a drill that diameter and a way to drill a hole throught the side of the intake manifold (that should be tricky!).

Sorry if my drawing skills do not make clear what I want to do.. Not very good at that.
 

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So, how can you possibly use it? The whole design is balanced based on the V6 design. How are you going to compensate for closing off one side? Wouldn't it just make more sense to work with a inline design supercharger?
 

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Discussion Starter #14 (Edited)
Yes, it would. The inline supercharger is $2000+. This one was $300 shipped and already has an intercooler, bypass valve and throttle body.

And why would I have to compensate for a side being closed off? The supercharger from Audi basically has a plenum too, closing off one side would force all the air to the other side, but as I mentioned, with the loss of one of the intercoolers.

So that's why.
 

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Yes, it would. The inline supercharger is $2000+. This one was $300 shipped and already has an intercooler, bypass valve and throttle body.

And why would I have to compensate for a side being closed off? The supercharger from Audi basically has a plenum too, closing off one side would force all the air to the other side, but as I mentioned, with the loss of one of the intercoolers.

So that's why.

I see, I can understand the logic there - so there are no internal channels in the supercharger housing to direct flow distribution? I'm still dubious as to whether you would see balanced flow to just one bank, but if it is completely open inside the 'plenum' presumably it won't matter. Has anyone else done this in your research?
 

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Arouse the DAMPFHAMMER!
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Welcome to K20a.org camprr! This is a very nice project :).

1. It's a design for a V6. What are you thinking!
No problem, you can easily adapt it with a collector of six into one plenum which adapts the runner part of the RBB IM. I think you already had something like that in mind. But think of following, the flange of the K24A3 was never designed to carry such a weight at this lever arm. This need some serious brackets with the block as basement.

3. It's drive-by-wire and the by-pass is also adjust-by-wire
Controllable, if you have the CAN matrix available. I am not 100 % sure, but VAG introduced first around 2003 CAN into their engine control stuff.

1. These cheap pistons on ebay (low compression) are they any good?
Neither I know reviews of it nor I did use it for one of my projects but a few here talked about the Nippon stuff. Try a search here at K20a.org or somewhere else:
2. Is there anything I need to be aware of in the K24A3 engine that is 'weak' or 'bad'?
I don't know the year and the type, but some of the K24 engines have very light rods in it (around 500 g, longer and lighter then the K20 rods), these aren't the best for boosting or revving it massively over stock conditions. Maybe someone know where the stronger rods cam in. I tend to say the higher revving version got the lighter ones...just my assumption.

3. The Throttle body for the Audi is a fly-by-wire jobby, anyone have any idea if KPro supports this? Or will I need to build something to 'convert this?
Challenging if you have no access to the firmware. FPro can maybe do it, as it can run the stock DBW TB's of Honda. It is likely the VAG version has a CAN interface.

4. The bypass valve is a simple DC motor with a variable resistor feedack, will KPro be able to do this?
Man, open your opportunities and go with an standalone. Nor FPro, neither KPro are able to do this properly. Their output channels can supply a PWM or analog voltage signal to a relais, which may can handle the bypass, but the bypass control is a closed loop feedback system, which need a closed loop control. Nothing on board with that limited Hondata tools. What you need is a proper ECU, supplying real DBW maps to be able to do a open loop thing, but with engine speed, MAP and TPS in one map or best would be to have it closed loop controlled with an feedbacked MAP signal.

BTW, I've integrated the Pierburg CWA pump (BMW N54 EWP) into the closed loop boost controller of my infinity with an tricked boost signal input. Works great, but the AEM Infinity has the capability to run such things. The Hondata stuff is very very limited, not regarding output at most, but regarding the over OEM stuff output channel mappings. Going with them for your aim is very challenging, at least very limited in use.

Are you open to discuss your Supercharger road? I am 99.9999 % sure a NOS or turbo system or a used SC kit would be cheaper. Your project has the potential to get cost additional 2000 Euro down the road if you do most (plenum collector transition, SC brackets, control stuff, wiring and fabrication, tuning) DIY and more if not.
 

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Discussion Starter #17
@LotusElise Thanks for that post, most informative. Take aways for me:
1. Yes, need to stabalize the whole thing at the bottom of the block (maybe as an attachement to the motor-mount there, that should be strong enough).
2. Seems like the news on the pistons is not bad news, so hopefully be OK to 300-350bhp. Ordering some conrods to go with those pistons to increase the redline some. (like 8500 or so and yes, changing the oil pump) My Audi TVS1320 goes to 20k rpm, so must work out pulley ratios before we go there. Hoping the ratio is 2.5:1 or so.. We'll see.
3. Probably going Megasquirt III, as there is plenty of Honda support, and there is a Drive-by-wire option: DBWX2 Drive By Wire Controller

Before tackling the internals of the engine, I need to take it apart (obviously). I've also ordered some bore-measuring equipment. I'll need to measure up the bores, so I can see what size they need to be bored to. My engine has 310,000km (from an automatic Accord and on LPG (gas)) so I need to work out what needs to be replaced and/or bored/honed/upsized. Might even go for a new head, if the valve-seats are too badly worn to get them gas-tight. Oil pump, sump etc etc are all being replaced as a matter of the Kmiata kit, so I'm not too 'worried' about those. Crankshaft will need to be carefully checked.

So my list is as follows:
1. Get the supercharger to fit on the engine (lot's of manufacturing/welding/thinking)
2. Check engine internals (measuring/ordering)
3. Order components for engine repairs (conrods/piston/head).
4. Send the engine to be bored/honed/whatever_is_needed)
The one thing I am a bit 'purturbed' about is whether I should go for low-compression pistons. Will I need those at the planned power levels (to avoid knocking)?
 

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Arouse the DAMPFHAMMER!
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😂...seems you are not interested in discussions of alternative empowering of your engine. Ok, no NOS and no Turbo. Seems your budget pot has a flexible money level 😉.

...Hoping the ratio is 2.5:1 or so.. We'll see.
Redline at 8200 rpm, safety to 8700 rpm gives you a ratio of 2.3:1.

Probably going Megasquirt III, as there is plenty of Honda support, and there is a Drive-by-wire option: DBWX2 Drive By Wire Controller
Around 1200 Euros, isn't it? Just 100 Euros away from my AEM Infinity 508 I have on my DAMPFHAMMER engine.

...Get the supercharger to fit on the engine (lot's of manufacturing/welding/thinking)
My assumption with done in DIY mode about 600 Euros at least and plenty of time doing the 3D CAD stuff to get it on the CNC for flange building before even able to start the welding.

Will I need those at the planned power levels (to avoid knocking)?
No need when you have 98 RON fuel available and do have a proper supporting header and a low enough intake temperature (50 °C and lower), which you need to integrate if not already available at the charger housing. I would keep the 10.0:1 CR to get it done and tuned. BTW, I hope you give the SC parts, which are capable for soap, a clean bath, especially for the intercooler.
 

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Discussion Starter #19
My assumption with done in DIY mode about 600 Euros at least and plenty of time doing the 3D CAD stuff to get it on the CNC for flange building before even able to start the welding.
Nope, just jo-loing it. So I'm hacking up the existing intake manifold, and using that to create a new manifold (CAD, I only use that in Cardboard Aided Design).. The problem is I would like to do it all in real CAD but: 1. I don't have the models for all the parts and 2. I'm not sufficiently skilled enough to do all the modelling required.

Around 1200 Euros, isn't it? Just 100 Euros away from my AEM Infinity 508 I have on my DAMPFHAMMER engine.
I've just learned that my ME221 will also do drive-by-wire 'stuff', and also can control an 'electronic' dump-valve, so sticking with that for now... But to be honest, the MS3 can also interface to CAN, there are a lot more people who are fimiliar with how it works, I can get 'free' help etc etc. I'm a great proponent of open-source and the flixibility it provides. The reason I got my ME221 is because it saves me the hedache of wiring the MX5 engine I currently have (it comes pre-configured for the MX-5 harness). And it's actually cheaper than MS3. But I am starting to run into limitations on it's possibilities (it does not have a built-in Lambda controller, for example)

😂...seems you are not interested in discussions of alternative empowering of your engine. Ok, no NOS and no Turbo. Seems your budget pot has a flexible money level 😉.
Actually, I'm trying to do it on the ultra-cheap (or as cheap as possible). My supercharger, intercoolers, by-pass valve and throttle body (along with two pressure sensors and a load of other stuff), were just $300. I challenge you to find a turbo for that money, let alone the other stuff (ebay, look for "06E145601H" and you find S4/S6/S8 superchargers). My engine is a 310,000km K24 out of a German Accord for 'just' $600 including all the bits I need (but it will need some work to refresh it). Where it gets extremely expensive (unfortunately) is the Kmiata stuff (~$6000 plus taxes and import duties). I hope to finish below $8000 total cost, we'll see. I'm hoping to do the exhaust-manifold myself, to save some money. But oil-pan, gearbox adapter, engine-mounts etc etc are a lot of 'figuring out' that someone else has already done. So it feels weird to do all that work again... But it also feels weird to pay that much money for it.

No need when you have 98 RON fuel available and do have a proper supporting header and a low enough intake temperature (50 °C and lower), which you need to integrate if not already available at the charger housing. I would keep the 10.0:1 CR to get it done and tuned. BTW, I hope you give the SC parts, which are capable for soap, a clean bath, especially for the intercooler.
Everything is going to be cleaned/painted/checked before it will be installed, but please don't misunderstand, not going for the 'showroom shine', the driving is always more important to me than the showing.. So where I can use an old bolt, I will. I see some builds using all-new bolts and I just think "what a waste of the budget, what was wrong with the old bolt?"

At the end of the day, don't we just all do what we feel like? If it makes more than 250hp, I am already happy. I've been thinking of just starting with the standard engine ~200hp and then adding the SC later. But it will hardly make a difference in the cost, as I will then need to buy an inlet manfold (~$700) and a throttle body (~$200). Just the effort required to get it running will be less.

I'm expedcting the engine refresh to cost approximately $200-700 depending on what I am replacing. I have not measured anything yet on the engine (it was reported to have slightly lower compression, so either valves or pistons).
 

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It would help to lean the blower assembly away from the engine at the top. That way the I-4 runners could 90 deg down towards the lower three coming off the blower. Then the 3 from the upper blower could 120 deg down and meet to a plenum in the middle.
 
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