Just a thought on new turbo placement & intercooler pipe

[DavidGTiR]

I was at a rolling road day on Sat at garage in Glasgow and noticed these guys were proper engineers/tuners that did everything in house. They showed me their twin turbo impreza estate and twin turbo saph cossie with an intercooler taking up the full front of the car. They make their own manifolds and the quality of them was amazing. I asked them for a price on a manifold for the R to take the turbo to where the battery is located as standard. He advised around 700 plus vat which i thought was not bad. I was thinking if i had more room then i could mount a larger turbo easier and have the hot air from the turbo sent down where the pipework usualy comes up on a FMIC, through the intercooler, back up and into the inlet manifold (which has been turned around so the inlet is on the drivers side, just undo the bolts and turn the top half of the inlet 180).

I remember seeing the R thats the quickest in Japland and it used an exhaust manifold like the one im on about. Hope this all makes sense and as far as i can think its a simple idea.

Here is a terrible drawing of my idea. :lol:

(isnt a pic of my engine bay, i took it off the "post pic of engine bay" topic)

 

[Anonymous]

I can think of a couple of problems with the idea.

1) Longer runners equal more lag
2) If using a larger turbo where will you mount the external wastegate (note that just using a single or two runners will cause boost creep)?
3) You'll be needing a downpipe of at least 3" diameter to get the most from a bigger turbo, so where are you going to route this?

 

[Anonymous]

First off, i forgot my password and have changed email so under a new username. :evil:

I can think of a couple of problems with the idea.

1) Longer runners equal more lag
2) If using a larger turbo where will you mount the external wastegate (note that just using a single or two runners will cause boost creep)?
3) You'll be needing a downpipe of at least 3" diameter to get the most from a bigger turbo, so where are you going to route this?

A.

1. This is one of those area`s where no one will ever agree on. How fast do you think the exhaust gases exit at the head on a turbocharged car, especially running higher boost and rpm ? Personaly i dont think an extra bit of length ie a few inches (especially if the runners are equal length) really affects lag in this case.

2 & 3. If you are moving the turbo, especially if you are going to use a larger one, the surrounding area will also need to be modified to suit ie heatwrap, relocated sensors and hoses etc so there will be room for the ext wastegate and exhaust pipe run which isnt really major hassle.

If only someone can find the pics of the black jap R that has this manifold then we could have a closer look at whats been done in that case. Also, if you look on the Ford forums most of the guys with Zetec RS Turbo conversions are using this same design of manifold. I think its from fiesta frenzy. The design idea was taken off the Focus WRC car and Sunny`s 178mph Fiesta that people have seen/heard about used to use the same design with no problems. It now uses the ramshorn design of manifold.

Please click on link and scroll down to see about the manifolds they use.

http://www.zetecturbo.com/ffmpands.htm

 

[Si..]

If only someone can find the pics of the black jap R that has this manifold then we could have a closer look at whats been done in that case.

this one??? the bigger picture can be found in the home page members pic's, under 'Beast'

i'm getting a manifold made up at the moment like this. and the tuner has already contemplated turning the inlet mani round the way you have said, its a lot more hassle than it looks.

 

[Anonymous]

Thats the one ! Cheers Si.

That is one cramped engine bay and they still have the inlet on the passenger side.

Cant wait to see pics of when your car is finished Si.

Can you please let me know what sort of problems you came across swapping the inlet manifold around ?

PS the garage i was talking about also had a R5 GTT running fuel injection with bike throttle bodies and tubular manifold. Sweet !

Cheers

 

[Anonymous]

Hi David,

Increasing the runner length will increase lag, it's not really something you can agree or disagree on, it is a fact and happens for these two main reasons.

1) Remember that the turbine spins because of the expansion of HOT exhaust gas over the blades, it does not spin because the exhaust “blows on it like a windmill”. If you increase the running length you increase the surface area for exhaust heat to dissipate through. Ceramic coating and wrapping the runners will help this.

2) Reversion is another problem with longer runners. When the engine has completed the exhaust stroke, there is a moment when the intake stroke starts and the exhaust valves are still slightly open. At this moment the cylinder is of a lower pressure than that of the exhaust manifold, so some of the gas rushes back in to the bore before the exhaust valves close. This reversion of flow slows down the velocity of the gas in the manifold and thus slows down the speed of which the hot expanding gases reach the turbo.

To properly design a good exhaust system you need to have the runners of a size long enough so that at the point where one exhaust pulse is slowed by reversion, the pulse from an adjoining cylinder merges to pull it along. This helps with cylinder scavenging meaning that less exhaust gas remains in the bore so more space is available to be filled with nice cool air fuel mix, and it also reduces back pressure considerably. All the time we have valve overlap, we will get exhaust reversion and this limits the mixture we can cram in to the bores and increases the cylinder temps which in turn limits the timing advance we can run, which also limits the power we can make. Total advance under boost is ALWAYS knock limited.

 

[Anonymous]

What web site was that taken from

I understand what you mean and you have certainly gone into detail but i think it is something you can argue about. Its like the "does going from 14" wheels to 16" wheels really affect my performace" question.

In a turbocharged setup, the exhaust gases are forced through the turbine of the turbo charger. This obviously causes the turbine wheel to spin up. That is why the blades are angled. If we were going to F1 spec engines then i understand you talking about the whole heat/reversion thing but i dont think it really matters here.

As far as im aware the reason for heat wrapping was to keep heat in as it can escape quicker and then let more air in on the intake stroke.

Plus, if you look at the manifolds some of the guys run in the states especially on some hondas they are a lot longer and they have no problems when using a good choice of turbo to see 400hp+.Also, im surprised they get so much power on some poorer manifolds. ie wastegate flange on only one branch of the manifold. A friend of mine built a 1.6 16v non vtec CRX with a very basic turbo kit and management (10psi, stock internals) only and this thing can keep with me in my R32 GTR and that has 456hp.

But its like anything in this world. There will always be a downside to the up.

 

[skiddusmarkus]

Never mind all that hocus pocus magic engine stuff.If you rotate the inlet manifold 180 degrees the entrance to it will be about 3" into your o/s suspension .I won't even start on all the cr*p you'd have to swap about and new brackets etc that will need fabricating.

 

[Anonymous]

Thats when you cut it off, re-angle it, then weld it back on. Cant see it being hard but i did notice there wasn`t much space. Still possibe.

 

[Anonymous]

lol It’s not from a website, I’ve built the odd engine in my time and it’s very basic exhaust principle.

It’s pointless comparing the cars you’ve mentioned, I’m not saying you won’t make power with long runners, I’m saying you’ll make more power and have a car that’s more fun to drive with the correct sized runners. A turbo charged Honda making 400Bhp is all well and good, but post up an example dyno plot and lets examine the power it’s really making. I’m sure the torque figure is pretty low and I doubt it makes 200ft/lbs until around 4500rpm, and I can guarantee that peak hp is reached somewhere around or after 8000rpm. It’s not really a very streetable set up and would only be good as a drag racer or dyno queen. On the road / track you want a car that makes a lot of torque low down in the revs so you can accelerate quickly and get some power on fast when coming out of corners.

You are right that hot exhaust gas moves faster, the reason for this is the hotter gas is expanding. You need to trap this heat in the exhaust system because if the manifold or exhaust system dissipates it, there will be less expansion and the gas speed decreases.

What you’ve said about the turbo is wrong, they really don’t work like that. The turbine isn’t a windmill that is blown by exhaust gas, it is a turbine that spins because hot gas expands over it. The hotter the exhaust gas, the more energy it contains and the more it will expand, therefore the turbine can extract more energy from it to accelerate the compressor wheel faster. This is really basic turbo principle, have a read up on it.

 

[Anonymous]

Ok, still cool as funk to have the turbo over that side though :lol: