albertz
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| posted on 13/1/05 at 07:51 AM |
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4AGE Inlet plenum question
I am in the process of modifying the inlet manifold on my engine to allow it to clear the bonnet line. The engine I am using is the TVIS version and I
also have a non TVIS as a spare.
What I have done is removed the original TVIS manifold and the sandwich butterfly thingy (technical term?) and replaced it with the modified manifold
from the non-TVIS engine. To make this fit I filled the gaps around the bottom of the mating flange, where the ports are different sizes. I connected
it all back up last night and it is all running, cant check too much though as there is absolutely no exhaust at all and I have a 2 year old daughter
trying to sleep
Anyway, my question is, what effect will I have from using the small port manifold onto the large port engine in terms of power, torque and power
band?
Also, the original engine wiring has a connection for the TVIS, what I have done is removed the sensor and connector from the sandwich thingy and left
it connected to the wiring, so that it doesn't confuse the ECU.
I hope some of the above makes sense to someone.
I know a lot of people have done this and I was simply wondering what the effects of the mod are. Thanks for reading.
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Rob Lane
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| posted on 13/1/05 at 09:08 AM |
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When you say you've filled in manifold gaps, do you mean in manifold? Have you matched roughly the ports?
I wouldn't worry too much on this for now, I shortened my plenum to get it under the bonnet.
It had the effect of moving the power band up the revs. It takes off like a VVT engine, in effect reasonable power up to 6k then off like a banshee
up to rev limit.
Found this actually useful as it gave control at lower engine speeds but just either took a shift down in gear or a prod on pedal to zoom off
overtaking.
That is the single biggest thing about the car, it's overtaking speed, passes cars very quickly. Trouble is nowadays that stresses the other
car driver !! Some *!rses get major upset and end up speeding up to follow you.
I'm sure others will come along with similar tales. The cars have that effect on people.
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albertz
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| posted on 14/1/05 at 07:42 AM |
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Rob, what i did was cut the bend out of the non TVIS manifold and welded it back together almost horizontal, i then turned the throttle housing
through 90 degrees so that the butterfly works through a vertical axis, everything else is as original.
The non TVIS manifold ports are smaller compared to the ports on the engine and they do not match exactly. When viewed from underneath there are some
gaps, where you can see into the chamber, these were filled on the manifold by filling with weld then dressing down level.
The ports are roughly central to each other but they are different in size, do you see this being a problem?
I am not going to be trying to break any land speed records when on the road, i just want a decent enough car that is reasonably quick. I cant wait to
get on the road and cause a bit of road rage
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Rob Lane
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| posted on 14/1/05 at 09:19 AM |
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The change would be hard to say, probably not noticeable in normal use.
There will be a step in the gas flow which ideally should be smoothed out as a purist.
There will be a loss of torque as the manifold has been shortened BUT I bet you will be surprised at the cars performance once it's on the road,
due to it's lightness.
Why not make up a new manifold from steel tube and plate that matches your ports if you're worried. You can make that a longer term project.
I had a link of a design but can't find it at the moment.
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DEAN C.
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| posted on 15/1/05 at 12:35 AM |
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Didn't Eddy Mclements do a similar manifold in steel tube?
JUST! managed to squeeze my tvis manifold under the bonnet standard.
Once I've finished a project why do I start another?
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