different intake manifolds

[turbodriver63]

hi guys. just curious, the s4 and the s6 have similar if not identical inlet manifolds which are longer than the s2 and rs2 inlets. are there any performance differences between the lot?
the reason i ask is, i need an s2 or rs2 manifold for my urq and want to buy the best only once.
cheers folks

[Error404]

IIRC the 3B inlet flows better than the ABY / ADU ones

[jogi730]

Depends what you are after (power etc).?
THere are other options out there ie. Wagner or Repo.
Here is a link to some Repo pics

http://www.s2forum.com/forum/showthread.php?t=34983

Hope this helps.
Cheers
Chris

[turbodriver63]

cheers error404.

http://www.s2forum.com/forum/showthread.php?t=34983

jogi730 i have to say, both the wrinkle painted intake malifold and your em are amazingwhere did you get them?
also if you dont mind me asking,do you remember roughly how much they cost. you can p.m me if you dont want to advertise it.

[terrybullwon]

All the info you need is here, Pro Mo has a section on the forum can be found here http://www.s2forum.com/forum/forumdisplay.php?f=68

8.3 sec / 1100hp proven intake manifold for I5, copied by competitors, ouperformed by none

http://promo.pp.fi/temp/imusudsi/IMG_1560%20(Large).JPG

Fits on to t85, t89 and B4 bodies.

Tomi Paavola uses first generation version of these CNC intakes in his record holder RS4.

http://compturbo.com/spotlight/1100+HP%20T4%20Turbo.php

Highlights:

-CNC machined runners and plenum bottom plate to ensure equal flow caracteristics to each pot
-round shape to endure enormous boost levels. I haven't heard any of these intakes had cracked ever, even because of backfire
-clears the original aircon rad
-clears original bonnet, but the x-member under the bonnet needs to be modified a bit
-clears all other obstacles in S2 engine bay, so fits into otherwise stock engine bay. Only parts that need modification are throttle cable and radiator shroud
-proven to work with 1100hp
-package includes custom fuel rail
-lifetime warranty
-in flowbench test gave 13-17 percent better flow on high cam lifts over AAN stock one.

I am pretty sure I was the first carage tuner in the world to copy the dual chamber design from Audi Sport parts in mid 90's when I made my first intake manifolds.

After building dozens of different types I ended up to the design used today.

Lead time is normally around 5 weeks. At the moment I am waiting for new batch of CNC parts, that should arrive any day.

Price 1400 eur with fuel rail, no powdercoating

Powdercoating adds 175 eur and appr. one week to delivery time.

[jogi730]

Both IM and EM are available from Pro_Mo Racing (or Repo on here). He is one of the sites sponsors. More info is available here:

http://www.s2forum.com/forum/forumdisplay.php?f=68

For prices, you need to PM him directly.
Cheers
Chris

[turbodriver63]

excellent. cheers guys

[kidashley25]

it depends what you like and what you want. They both featured a 230 PS (169 kW) 2.2 litre, 5-cylinder engine with turbocharging and an intercooler, with 350 N·m (258 lb·ft) of torque.V8-powered versions of both S4 and S6 were available. The S4 version sported a 280 PS (206 kW) engine (the same "ABH" engine as in Audi V8), the S6 had an upgraded engine "AEC" with 290 PS (213 kW).

__________________
kidash - Audi Parts

[Error404]

?

[turbodriver63]

sorry kidashley25, i dont understand what you mean!

[jogi730]

Turbodrivver,
I don't know what sort of power levels you are going for, but another alternative is to use AAN IM - good option up to about 450bhp (much cheaper too).
HTH
Cheers
Chris

[mcandmar]

The AAN manifold on your S4/S6 is a better design than the S2 version due to the throttle body location, in theory it should flow better and more equal over all cylinders. Folks have fitted them to S2's but its a messy solution trying to fit the radiator around it.

Remember the intake path is shorter and less restricted on the S4/S6. Hence all the various manifolds available for an S2 with a front mounted throttle body to do away with the pipe over the engine and the 90 degree turn before/after the throttle body. Shorter intake path is what its all about.

So to say which manifold is better you have to consider two things, the manifold itself in terms of flow and distribution to each cylinder, and the throttle body location which dictates the intake path and length of plumbing required. In short a front mounted manifold like the Wagner is a much better solution than the stock setup for an S2. But i wouldn't be surprised if the AAN manifold performs better when you get into big HP numbers.

Also i think the intake runners on the AAN manifold are longer which adds another variable.

[|Maku|]

Also i think the intake runners on the AAN manifold are longer which adds another variable.

Talking about runners length, does it improve vacuum area if stock runner are made longer by adding trumpets inside the manifold?



How do tuned intake runners work on your car?

The intake system on a four-stroke car engine has one main goal, to get as much air-fuel mixture into the cylinder as possible. One way to help the intake is by tuning the lengths of the pipes.

When the intake valve is open on the engine, air is being sucked into the engine, so the air in the intake runner is moving rapidly toward the cylinder. When the intake valve closes suddenly, this air slams to a stop and stacks up on itself, forming an area of high pressure. This high-pressure wave makes its way up the intake runner away from the cylinder. When it reaches the end of the intake runner, where the runner connects to the intake manifold, the pressure wave bounces back down the intake runner.

If the intake runner is just the right length, that pressure wave will arrive back at the intake valve just as it opens for the next cycle. This extra pressure helps cram more air-fuel mix into the cylinder -- effectively acting like a turbocharger.

The problem with this technique is that it only provides a benefit in a fairly narrow speed range. The pressure wave travels at the speed of sound (which depends on the density of the air) down the intake runner. The speed will vary a little bit depending on the temperature of the air and the speed it is moving, but a good guess for the speed of sound would be 1,300 feet per second (fps). Let's try to get an idea how long the intake runner would have to be to take advantage of this effect.

Let's say the engine is running at 5,000 rpm. The intake valve opens once every two revolutions (720 degrees), but let's say they stay open for 250 degrees. That means that there are 470 degrees between when the intake valve closes and when it opens again. At 5,000 rpm it will take the engine 0.012 seconds to turn one revolution, and 470 degrees is about 1.31 revolutions, so it takes 0.0156 seconds between when the valve closes and when it opens again. At 1,300 fps multiplied by 0.0156 seconds, the pressure wave would travel about 20 feet. But, since must go up the intake runner and then come back, the intake runner would only have to be half this length or about 10 feet.

Two things become apparent after doing this calculation:

1. The tuning of the intake runner will only have an effect in a fairly narrow RPM range. If we redo the calculation at 3,000 rpm, the length calculated would be completely different.
2. Ten feet is too long. You can't fit pipes that long under the hood of a car very easily.

There is not too much that can be done about the first problem. A tuned intake has its main benefit in a very narrow speed range. But there is a way to shorten the intake runners and still get some benefit from the pressure wave. If we shorten the intake runner length by a factor of four, making it 2.5 feet, the pressure wave will travel up and down the pipe four times before the intake valve opens again. But it still arrives at the valve at the right time.

There are a lot of intricacies and tricks to intake systems. For instance, it is beneficial to have the intake air moving as fast as possible into the cylinders. This increases the turbulence and mixes the fuel with the air better. One way to increase the air velocity is to use a smaller diameter intake runner. Since roughly the same volume of air enters the cylinder each cycle, if you pump that air through a smaller diameter pipe it will have to go faster.

The downside to using smaller diameter intake runners is that at high engine speeds when lots of air is going through the pipes, the restriction from the smaller diameter may inhibit airflow. So for the large airflows at higher speeds it is better to have large diameter pipes. Some carmakers attempt to get the best of both worlds by using dual intake runners for each cylinder -- one with a small diameter and one with a large diameter. They use a butterfly valve to close off the large diameter runner at lower engine speeds where the narrow runner can help performance. Then the valve opens up at higher engine speeds to reduce the intake restriction, increasing the top end power output.

LINK: http://auto.howstuffworks.com/question517.htm


Tim's Manifold Tech:
Intake manifold design should be a copy of what the new cars are doing. With lots of experimenting, we found some horsepower hiding in there. All the new go-fast cars are taking advantage of a natural phoneme called "Inertial Supercharging." First, a carbureted engine at best, can only be about 85% volumetric efficient. This is because it has to restrict the air flow, to create a low pressure area, to draw in the fuel.
Definition: Reversion Pulse: Did you ever take off your air cleaner and see a mist of sputtering fuel mixture right above the carb? That's the reversion pulse pushing air and fuel out the intake.

The reversion pulse occurs when the intake valve opens and the left over combustion pressure pushes spent gases into the intake. How much depends on the amount of valve overlap, how restrictive the exhaust system is, and at what RPM you are at.

The newer fuel injected manifolds work like this. The reversion pulse that comes when the intake valve opens, runs backward up the runner and bounces off the plenum. At the right RPMs, it will start to resonate. This pulse then goes back down the runner pushing up to 130% more air in front of it! The air speed gets up to about .8 Mach. This is why if everything is equal, fuel injection will make more horsepower than carbs. The higher air speed in the runners gives you better cylinder filling at the lower speeds which gives you better bottom end. Arrange the runners in the plenum so that the reversion pulse bounces off a hard surface. You don't want the pulse to blow down the opposite hole.

Intake Sizing: The size of the runners should be the same as the intake port, and the volume of the runner should be about 100% of what that cylinder displaces. The length of the runners "Tunes" the resonance at which point this effect will boost the intake. The longer the runner, the lower the RPM for the effect. The plenum size is usually 100% of the total engine displacement.
Volume = 3.14 * (radius) * (radius) * length

The intakes usually end up being about 23 inch long runners, 1 1/2 inches in diameter, connecting into a 5 inch diameter plenum that is about 7 1/2 inches long. This is about 100% of the cylinder volume for the runners and the plenum is about equal to the total engine displacement for a 2276cc engine. The runners usually come off the plenum at a 90 degree angle with the air valve mounted on the end (just like the new cars).

LINK: http://www.dune-buggy.com/turbo/intake.htm

http://autospeed.com/cms/title_The-Nissan-VG30DETT/A_109870/article.html

Intake System

The intake system design had to balance two opposing outcomes:

* the smaller that the intake runner diameters were made, the greater the frictional losses (and so pressure drops)
* but the larger the intake runner diameters, the slower the airflow speed, resulting in a decrease in cylinder filling, especially at low rpm

In addition, simulation and testing showed that long intake runners resulted in better torque development at low engine revs - however, fitting long runners into an already crowded engine bay was going to be difficult. Runners that were 360mm long gave peak intake efficiency at 4400 rpm, while lengthening these to 480mm dropped the peak intake efficiency revs to 3600 rpm. Since one of the goals of the engineers was strong bottom-end torque, the longer runners became a requirement. Further testing showed that a runner diameter of 48mm worked well with the 480mm long design.

[It's interesting to note the major amount of development that occurred in tuning the intake system in this turbocharged engine. Many turbo engines - including Nissan's own RB26DETT Skyline GT-R engine - have no intake resonance tuning at all.]
Click for larger image

Once 480mm (nearly 19 inch!) long intake runners had been decided upon, the next question was how they'd be fitted under the bonnet. The previous model VG30DE had placed the plenum chamber centrally on top of the V6, with relatively short but direct runners connecting the plenum to the intake valves. The measured pressure drop with this arrangement was 85 units.

[The units used are not completely clear - they may be mm of water at 4.4 cubic metres/minute flow.]

The first prototype VG30DETT intake system design placed a plenum chamber above each bank of cylinders, with the intake runners for that head connected to the plenum above it. This required that each runner go through nearly a U-turn, and so was called the 'U-turnport' design. The pressure drop of this design was, however, very high - being measured at 105 units, or nearly 24 per cent higher than the original VG30DE design with the centrally-located plenum chamber.

A 'crossport' design was then built, where the plenum chamber feeds the opposite cylinder bank. This design allowed the retention of the long intake runners but gave a measured pressure drop of only 80 units - better than the VG30DE design, despite the use of intake runners nearly twice as long. The change from a U-turnport to a crossport design resulted in a 5 per cent increase in peak power.

The intake system ahead of the intake manifold was also extensively developed. The airfilter housing used two filtering elements to provide sufficient filtering area within the tight confines of the engine bay. Only a single airflow meter was used, but the junction where the duct splits to feed each turbo was extensively developed. The final design used a very long radius inner bend reducing measured pressure drop by 77 per cent over some of the designs trialled. Together with the use of a bellmouth at the entrance to the airflow meter, these flow improvements increased peak power by 2 per cent.



http://forums.evolutionm.net/engine-...ld-thread.html

Intake port runner length: Higher speed engines benefit from short runners. Low-speed and mid-range torque generally shows gains from longer runners. Turbo applications generally findbest results with long runners, which provide a broad, flat torque curve at low speeds, while the turbo keeps the top end strong.

[turbodriver63]

wow my brain hurts after reading that. you have put some serious thought into that
i actually have a aan engine and inlet manifold but its going into a urq. i was told it was near impossible to fit the aan im in a urq because it fowls the rad
personally i am looking for about 400bhp area.

[repo]

Forget all that jibberish above and take Wagner.