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longer intake runners?
by
VWSmokr
on 05 Apr, 2025 06:46
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Injected gasoline engines generally have better low rpm torque with longer intake runners. Wondering if a factory 1.6N.A. diesel intake manifold(ported/polished, obviously) would help an intercooled 1.6 IDI/turbo motor with better low rpm smoothness/torque, and possibly better highway fuel mileage when running a deep overdrive 5th gear.
Thoughts?
J.R.
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#1
by
ORCoaster
on 05 Apr, 2025 18:14
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Nice to see you back.
I think I read somewhere that the box on the 1.6 IDI was very good for intake feed. So your idea isn't too far fetched. But how do you plate it off so you can be pushing 10 psi down the tubes?
Maybe a center pipe on a plate that gets welded across the front of the box? Something bolt on with studs welded to the box?
What might this contraption look like?
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#2
by
Dakotakid
on 05 Apr, 2025 19:51
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This topic was discussed years ago here. OR is pointing out the work needed.
As far as low-end response I doubt it.
Let me ask you this: are you spending time porting the exhaust and intake holes in your current head? Please tell me you are not trying to push additional air through the straw-ports they come with.
I only have one 1.6 left (have moved on rather heavily into alh engines) and it is judiciously ported with a healthy KKK 24 and I have NO turbo lag. Grunts right off the bottom any time the crank is turning. Rips right to the top. Run injectors shimmed to 2650 lbs.
Define "smoothness." You mean wimpy purring?
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#3
by
fatmobile
on 07 Apr, 2025 18:28
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If you have a stock turbo, you're limited to something that will fit between it and the head.
With the VNT-15 hanging so low you can use a gasser intake,
with it's longer runners.
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#4
by
VWSmokr
on 09 Apr, 2025 02:33
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Thanks for the input. Yes, the stock head needs P&P. As to air input from the intercooler, a bolt-on plate should do it. Installation will be in a VW Dasher (engine is longitudinal in chassis), so there is more room for intake mods than in a Golf or Jetta. Seems like it would allow for about 10-12" of individual runners to the ports, hopefully an improvement over the 3" of the stock turbo intake.(?) As to the smoothness... never heard ANY diesel "purring" at idle! Funny!
J.R.
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#5
by
RabbitJockey
on 09 Apr, 2025 09:51
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the simplest solution for this idea would be to use an intake manifold from a gas 8v vw. for better performance send it off to
https://www.scientificrabbit.com/ and have them work their magic.
tuning like this for a specific rpm i think is kind of negated by using a turbo, because the turbo has a huge effect on where the power will be in the rpm range. In a race application it makes sense but a street car i think cost and packaging are bigger factors, the stock 1.6td intake is definitely awful but adding a log style plenum to it resolves most of that without affecting packaging too much
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#6
by
fatmobile
on 09 Apr, 2025 20:49
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I have wondered what it would take to turn the NA airbox into an air to water intercooler.
It could be made pretty roomy without the air filter in there.
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#7
by
VWSmokr
on 10 Apr, 2025 02:31
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Any ideas on effective air cooling comparison between an air-to-water (approx. 12" x 4") and an air-to-air (approx. 30" x 5") intercooler setup? One rumor is that air-to-air works better for regular street driving. IDK! Ideas?
J.R.
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#8
by
fatmobile
on 10 Apr, 2025 18:10
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I think the main difference between the 2 is the plumbing.
smaller hoses are easier to route than fat air pipes.
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#9
by
JoeLlamahead
on 14 Nov, 2025 09:57
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“I have wondered what it would take to turn the NA airbox into an air to water intercooler.
It could be made pretty roomy without the air filter in there.
Report“
I’m thinking exactly the same thing . I just gotta figure out how to mount the turbo so it will clear the big intake manifold .I could flip the exhaust manifold but then how well will the oil drain back to the sump?
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#10
by
ORCoaster
on 14 Nov, 2025 18:35
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Stick one of those oil cooler evaporators in the intake box. Run water through it instead of oil. You could have a second evaporator in the grill and just use a small 12 volt pump to circulate it.