Custom Inlet Manifold

So after the great number of responses on the ‘Next Steps’ thread, I am looking into a custom inlet manifold.

I’ve seen a Starlet one for sale, wondering if this would be compatible and what sort of bodging would be required and also what sort of gains could be expected?

Here it is:

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Low Rider

Poindexter
Founding Member
Moderator
Club Member
Less restriction, better flow, which leads to more power + torque.

I’ve uprated m the exhaust manifold, and so thought it would make sense to also do intake manifold.

That's quite a general goal. The stock inlet manifold and the one Frank mentioned (attached), have pretty long runners and are aimed at the lower rpm range for the engine. Being a small displacement engine, diminishing gains set in fair quickly which makes the gains fairly small.

Matt Humphris has a selection of intakes on his shelf all ready to go. I've not seen anyone post up any definitive proof of gains when using a different intake but, perhaps Matt may have some, as he's built a lot of rally cars to date.

Aside from forced induction, the only way to make good power gains, once you've done the usual upgrades, is to open up the engine and/or rev it more, which is why a lot of people opt for individual throttlebodies. It however gets expensive very quickly.
 

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That's quite a general goal. The stock inlet manifold and the one Frank mentioned (attached), have pretty long runners and are aimed at the lower rpm range for the engine. Being a small displacement engine, diminishing gains set in fair quickly which makes the gains fairly small.

Matt Humphris has a selection of intakes on his shelf all ready to go. I've not seen anyone post up any definitive proof of gains when using a different intake but, perhaps Matt may have some, as he's built a lot of rally cars to date.

Aside from forced induction, the only way to make good power gains, once you've done the usual upgrades, is to open up the engine and/or rev it more, which is why a lot of people opt for individual throttlebodies. It however gets expensive very quickly.

Yes I don’t think I can afford to go down the jenvey throttle body route
I did actually have a look at some bike throttle bodies for £150 on eBay. I understand the stock ecu cant run these but do I then have to get a stand-alone ecu or can I just get the stock one mapped by tornado?
(I don’t fancy paying for an Omex as their too expensive)

And yes I do have some head work and pistons planned.

Will also inquire with Matt on other intake options.

Appreciate the advice as always.
 
Have dropped Matt a message regarding a custom inlet manifold, as the route of going for an Omex and ITB's is out of my budget.

Will update on what he says in case others are interested as well!
 
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Stand alone is a must. You dont have a maf with bike throttle bodies

So it turns out Tornado Systems can run throttle bodies on the stock ECU, provided I have a plenum.

I am guessing the MAF will go on the plenum then.

But I have no idea where to get a suitable plenum from?
 
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So it turns out Tornado Systems can run throttle bodies on the stock ECU, provided I have a plenum.

I am guessing the MAF will go on the plenum then.

But I have no idea where to get a suitable plenum from?

yes they can Because it will put the maf in front of it like on the gti-r.

custom fab work is most likely your only option.
 
thats a big plenum, your maf is scaled to about a 50mm dia aperture
a plenum of nearer to 50mm has more chance with the self learn type of ecu you have

Do you have any in mind?

If not, I can call Tornado and ask them what plenum they have used in the past on bike throttle bodies to run with stock ECU, as I'm assuming they've already done a few in the past.

Also, what is this new NATS delete option that they offer? Does that mean the ECU basically becomes equivalent to a standalone one? (in which case I wouldn't need an MAF anymore as I then have the freedom to choose, as on an Omex?)
 
thats a big plenum, your maf is scaled to about a 50mm dia aperture
a plenum of nearer to 50mm has more chance with the self learn type of ecu you have

Yes but if I am getting the ECU remapped anyway by Tornado, then wouldn't 80mm be a better and less restrictive option?
 
okay I plan to use gsx600r throttle bodies on the stock ecu which tornado can map.

I have contacted bogg brothers for them to do the custom plenum (for a common MAF) and then fit everything in.

But just a quick thought, can I use the gsx600r airbox as my plenum? And just cut an MAF mounting point into it and also cut it to size as it seems a bit large? (Using this airbox would avoid the hassle of getting a custom plenum made...)
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frank

Club Member
the self learn ecu,s are more problematic to map apparently, auto correcting fueltrims etc, so you are making it harder by having such a slow flow of air going past the maf
a 2.0 is inhaling more air
personally, i would be concentrating on raising the compression instead
 
the self learn ecu,s are more problematic to map apparently, auto correcting fueltrims etc, so you are making it harder by having such a slow flow of air going past the maf
a 2.0 is inhaling more air
personally, i would be concentrating on raising the compression instead

Ah okay I understand now, thanks Frank.

And yes I do also have a headskim planned to raise the CR, and some A14net pistons....

Just want to collect as much research to get everything done ASAP as I’m impatient😂
 
So I went to my mechanic to inquire about getting an inlet manifold made to fit the GSX600R throttle bodies and he's said I need to give him a spare K11 inlet manifold for him to carry out the necessary work.

Only problem is, I am struggling to find a CGA3 inlet manifold - is the coilpack CG10 inlet manifold identical? (as CG10 ones are much more readily available)
 
Is it possible in theory to run bike throttle bodies with the MAF disconnected?

Because the way its looking, my throttle bodies will be fitted into the car a week or two before I get the remapped ECU from Tornado, so can I still use the car for that weeks gap? or will the car simply not run AT ALL on the stock ECU. And I am also having thoughts about driving to Tornado Systems myself to get the ECU mapped while the car is on the dyno, for a more effective result, but I don't know if I should risk driving the car on bike throttle bodies and a stock unmapped ECU for a 2 hour journey...

I have seen a post on MSC of someone running bike carbs on a CG13 on the stock ECU and was wondering how it would be possible... - apparently he/she had all the sensors disconnected (MAF, TPS and dunno what others there are tbh)
 
with the maf disconnected your ecu uses the tps and rpm signals to map the injectors and sparks

Ah right, so that means in theory I could run throttle bodies on the stock ECU as a temporary measure, provided everything else is connected up?

Thanks for the reply by the way.
 
Found this online. I know a lot of people on here will already know what Alpha-N is but for other novices in this field on this forum (like me!), here is one of the better explanations (imo) I found on the web:

I know many folks on this board understand quite well what Alpha-N is, but this is for those who don't understand it. I remember how that felt, so I will offer my version of an explanation.

An engine management computer, regardless of how sophisticated or crude, really only controls two parameters. The ignition timing and the fuel delivery. The computer (DME or some aftermarket brand) uses an array of input sensors to try and determine what state the engine is in at any point in time. Is it loafing along on the freeway at low rpm, or at max throttle climbing a hill at high rpm? Is it hot outside so that the air is thin? Or is it butt cold and the air is real dense?

The list goes on, but the goal of the computer at all times is to sample its input sensors and then determine the appropriate output signals for ignition timing and fuel delivery (usually this determines how long the fuel injectors fire, which is called the pulse width, but it can also entail "when" to fire the injectors if the injection is sequential).

The two most important things that the computer wants to know in order to determine spark and fuel are: 1) engine load, and 2) engine rpm.
Engine rpm is easily determined from a crank sensor. But engine load is a little more tricky. The best parameter to use in determining engine load is the MASS of air entering the engine at any time. If you can measure the mass of air directly then you are well off. Current BMW's do just this with what is called a MAF sensor, or mass air flow sensor. This is usually some type of heated wire or film, which is cooled by the air flowing over it. In order to keep the wire at the same temperature additional electrical current must be provided, and the measure of this extra current gives a fairly direct indication of the mass air flow.

Our E30 M3's used a similar system, although it measures the VOLUME of air flowing into the engine. The sensor is called an AFM, which stands for air flow meter. The volumetric flow is determined by how far a flapper (or barn door) is pushed aside by the incoming air. The flapper is connected to a potentiometer (variable resistor, POT, wiper, there are many names). But for the computer to know how much fuel to mix with the air it needs to know how many molecules of air are coming in, and that can only be determined by knowing the MASS of the air, not just the volume. So, we need to combine the AFM air volume signal with an air TEMPERATURE measurement Then the air mass can be determined. So we are ok.

Note that in both cases the computer has some hard data on how much air is entering the engine, so if you improve engine breathing (header cams etc...), the basic code will still sort of work as the computer is aware of the additional air. It's not perfect, but it works ok most of the time for changes that are not too drastically different than the baseline.

Alpha-N is different. Here there is no direct measurement of either the mass of air, nor the volume of air entering the engine. That way any possible obstruction from either a MAF sensor or AFM sensor in the intake path is removed. The air can flow right into the engine unobstructed. So how does the computer know what to do? It still has rpm info from the crank, but it can't measure the mass of air coming into the engine for fuel mixture determination?

The answer, in a crude sense, is that you "train" the computer what to do in a given situation (on the dyno). For every possible combination of throttle position and rpm, the tuner determines the appropriate ignition timing and fuel delivery to yield max power but not incur detonation. The computer just remembers all this (in the form of maps which are stored on a chip), and when it sees a certain combination of rpm and throttle position in the field, it just says "what did they tell me to do in this situation?" and does that.

So now throttle position and RPM are the two dominant input parameters to the engine computer. This is where the Alpha-N name derives from. Alpha for the angle of the throttle plates and N for RPM.

Now if you have an Alpha-N system, and add a hotter set of cams that allow more air into the engine, but you do not reprogram the Alpha-N computer, then the computer has no knowledge of the extra air now entering the engine and it just gives the fuel and spark that it was told was appropriate for the milder set of cams. One can see how this could be a problem. Your mixture especially, but also your ignition timing will be way off. If your mixture goes lean you can potentially damage the engine. That is why folks say that an Alpha-N system needs to be retuned everytime you make a change to the engine. The computer is "flying blind" to some extent, although it does at least have an air temp sensor and a barro sensor to try to compensate for density changes in the air due to temperature and elevation.

I have oversimplified some subjects to make it easier to understand, and as usual there is probably more that I did not say than that I did say about Alpha-N, but hopefully that gets some folks a little closer to understanding it.
 

That is actually pretty cool ngl.
But says will only work with post 08 OBD2 cars?

I recently bought a fault code reader to connect my OBD2 port (to remove EML) and it failed to connect, was told its because my car is too old :(...
 

frank

Club Member
if it does work you can compare the spark mapping with the maf connected and disconnected, for programming a det3 or whatever
you will only get a narrowband afr signal with yours tho
 
if it does work you can compare the spark mapping with the maf connected and disconnected, for programming a det3 or whatever
you will only get a narrowband afr signal with yours tho

Ah right I see, but I'm not knowledgeable enough so would probably have to get someone to program the DET3 for me, but then this gadget should aid them in setting up the car in the best way.
 
Does anyone know where the best place would be to mount the MAF sensor on this airbox?
The MAF has to go after the filter so I was thinking somewhere along the bottom of the airbox, near the 4 rings?
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The maf needs to measure the airflow. So make a single pipe coming from the filter going to the airbox and place it there. Put a mesh in front of it to straighten the air flow
 
The maf needs to measure the airflow. So make a single pipe coming from the filter going to the airbox and place it there. Put a mesh in front of it to straighten the air flow


Ah okay I see, but my initial idea was to have the filter inside the airbox (as it is on the bike), or should I just go for the single intake pipe with a cone filter on the end?


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