I'm looking for some ideas for intake plumbing. I need to plumb the MAF and air cleaner to the throttle body. I guess a pod filter but I don't know. Can you give me some ideas please.
I have a pod filter behind the passanger headlight. For most of the journey from air flow sensor to throttle body I used some black ribbed ducting (rubber). Pretty sure I got it from purple pig. I think the inside diameter is around 90mm. I have used a section of aluminium tubing in the engine bay as I needed something solid to insert the air temp sensor into. I have had the aluminium section HPC coated to reduced heat soak (it runs about 8 cm above the headers).
Probably miniscule in a naturally asperated engine (not turbo), but ribbing is probably going to be quite restrictive in the airflow due to the turbulance created. Also i have seen this stuff colapse inwards in turbo charged applications.
These comments are probably totally irrelevant without forced induction, but it thought i would throw them out there.
Polished alloy or stainless looks good. Mandrel bends and polished pipe are available off ebay fairly cheap, and if you dont have tig welding facilities, silicon joints can make life easy, even in place of the bends.
In the past i have used a combination of mandrel bent 3" stainless steel bends and pipe with silicon couplings to make up some pretty crazy intercooler plumbing. Looks good and works well. Try and go with alloy though as it is lighter and easier to work with.
Also i was talking to a guy at the nationals (dont know if he is on here) who had used cake tins to make an air box. Appeared to work well.
I'm looking for some ideas for intake plumbing. I need to plumb the MAF and air cleaner to the throttle body. I guess a pod filter but I don't know. Can you give me some ideas please.
Peter
Hey Peter,
I used some silicone tube to adapt from the Throttle body to the MAF and a K&N POd Filter. The Temp Sensor is glued into a small hole I made in the silicone tube, seem to work ok. Is not a cold air system but am not looking for that kind of small perf improvement. Got the tube from Autobahn.
Gregg, OTR (over the radiator) intake designs commonly report 10-15kW gains compared to the the factory airbox, which I believe on the VE draws cold air from inside the front guard. I don't have any real proof, but I reckon a pod filter drawing air from behind the radiator is probably worse than a modern factory setup, let alone a custom cold air intake. It would certainly be interesting to log the intake temps and compare different designs.
I would look at an over the radiator system (OTRCAI) made from decent material. There are utubes around of ebay OTRCAI which literally collapse on themselves under wide open throttle.
The boys in blue generally frown on Pod filters more than they do OTRCAI.
And the MAF does not need to stay. Whilst they are still substantially better than the early LS models, gains can still be made via a tune and basically the MAF is wasted weight and space.
I know of some fellas doing custom OTRCAI for FI applications and others. I will invite one of them to make comment.
I am sceptical about what the real gains are of cold intake systems. They do offer a performance improvement, but at what rev range under what conditions. I suspect your 15kw would be at peak power when the engine is generating heat.
A dyno print out would be interesting to see. Im sure there would be one somewhere on the net.
Yes your right the rubber tubing is metal ribbed and yes it would create some turbulance which is why I went for 90mm id whilst my throttle body is only 75mm id.
In regards to surfaces. The inside surface of the intake should not be too smooth either as this will also create turbulance as the air will stick to the smooth surface.
Seems the biggest improvement is in the Torque, and power improvement is right up top.
It appears that graph is going from a factory intake that is more restrictive so im not sure how accurate that is.
Dont get me wrong, there will always be improvement gains from cold air. It is more dense and hence you get more oxygen with the same volume of air. I just think that sometimes CAI is hyped a bit.
Cold air does make a big difference to an LS1. Not just because it's denser but because the LS1 employs an IAT sensor (Intake Air Temp). The ECU uses this temp reading when determining how much ignition advance to give the motor. That's where the power gains are made.
Cheers
__________________
Mike Murphy
Melbourne Australia
The ECU uses this temp reading when determining how much ignition advance to give the motor.
Yes, agreed. The improvements of cold air are well proven in both injected and carby applications. You only need to go to a drag strip and watch the cars get faster as the night air gets cooler to see this.
Thinking about this further, this was most likely done by bringing the car to operating temp and then running on the dyno with what appears to be a 3rd gear pull (i think). There would most likely be even more benifits over time with the heat soak in the engine bay (especially if on a track).
I imagine in a cobra this would not be such a problem though with the hood scoop and side vents.
Thanks for all the info. There is a wealth of knowledge on this forum. From what I understand mafless is the way to because it removes another restriction from the intake path. For the time being I will install the Maf. There is a lot of discussion about cold air intakes. It's pretty hard find a point where there's cold air in these engine bays.
Greg,
Your setup looks ideal, Is the silicon connecting tube stepped or are throttle body and MAF the same diameter?
Peter, I know on the LS2/L98/LS3 the throttle body and MAF are both 90mm outside diameter. So a single piece of constant diam pipe should do the trick for us.
Regarding Gregg's photo, I would be inclined to draw air from the bottom of the engine bay rather than at the top where stagnant warm air will be collecting (no offense Gregg, just my opinion!). Perhaps a 90 degree elbow pointing down at the point where Gregg's air filter is located? I think Ben (Kenmer kit) has done this.
Also the hood scoop might draw air into the engine bay but it's well behind the pod filter and there's no turkey pan / carby creating a vaccum and drawing air through the scoop like on the original cars, so the actual flow is questionable.
draw air from the bottom of the engine bay rather than at the top
Thats how they do it with a lot of the jap imports. Through into the wheel well is also common, but i imagine dirty.
They actually make an attachement that you can plumb in that has a valve that opens if the intake sucks water. Pobably useful if used at the nationals
Is there room next to the radiator?
RE: mafless - This helps reduce the impact of leaks in the intake as well since MAP sensors work off intake pressure instead of air flow like the MAF (i am assuming thats how it is done, i have no experience with the LS engines yet). I think you would struggle to notice any performance increase mafless on a stock engine as there are more restrictive parts in the system. Some MAF sensors have a filter screen on the front that can create some restriction, i have known people to remove these (dont know if this is on the LS1).
Thanks for all the info. There is a wealth of knowledge on this forum. From what I understand mafless is the way to because it removes another restriction from the intake path. For the time being I will install the Maf. There is a lot of discussion about cold air intakes. It's pretty hard find a point where there's cold air in these engine bays.
Greg,
Your setup looks ideal, Is the silicon connecting tube stepped or are throttle body and MAF the same diameter?
Peter
Hi Peter, Yes, it is stepped, I cant remember the sizes but all I did was measure the throttle body and took the MAF with me to measure up and they ordered in the tube.
One day I might go the Cold air intake. Ian at CR has a neat Cold Air Intake that goes over the top of the Radiator. Probably when I take it on the track a few times and fingure out how to drive it first.
Cobra Make, Engine: Harrison #73 with an L76 6 litre CHEV, T56, 6SPEED,R32 Rear end.
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Quote:
Originally Posted by sambo
Peter, I know on the LS2/L98/LS3 the throttle body and MAF are both 90mm outside diameter. So a single piece of constant diam pipe should do the trick for us.
.
Hey Paul, on the L76 6 litre, the throttle body is 98mm O.D and the MAF is 93 mm O.D.
I built an under radiator cold air intake when I was running the stock manifold. It's made from 4" stainless and incorporates the IAT sensor. I'm running MAFless.
The induction noise was nice. Louder than the super quiet rego exhaust.
These days I get cold air from the hood scoop.
Cheers
__________________
Mike Murphy
Melbourne Australia
Last edited by Aussie Mike; 10-28-2009 at 02:30 PM..
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