Intake/Plenum Design

[LondonBenji]

Okay so here is a discussion I would like to have:

What ideally would be the best (in theory or in reality) intake/plenum design for NA? For FI?

What general rules for design should you follow NA? For FI?

I have seen several designs like the ones below, what are the advantages/disadvantages for each?

Tapered intakes:

Mclaren F1

F430/Jun(Skyline)/Nissan S13 - All attached.


Tube style ala Top Secret 350z (and similar to what I think JDMFantasy is working on):

Box type ala majoola inbetween the two HUGE intercoolers - Attached

Or individual throttle boddies ala A1 Turbo's:

Can you use ITB's for FI?

 

[LondonBenji]

From what I understand with FI it doesn't really matter so much, much like exhaust design for FI, just make it large and not have an restrictions in the flow. Feel free to flame me if I am wrong

But what about the capacity and what not? I know there is a lot of complicated stuff like pressure and whether or not all cylinders are getting the same amount of air.

 

[4000GT]

As a wise man once told me...

In FI, as you picked, as long as each runner can supply more air in each runner than the head can consume, it wont make any difference, within reason you had might as well get the design that fits best and is easiest to design. An NA application is where the intake design is more critical. Some people still want to build in NA principles into FI manifolds which is fine, personal choice it just wont have the same impact. Other people want to build a good quality manifold to test its outcomes to and remove it as a future possible restriction (like me), and are interested in the design and want to learn pratically and theoritically in the 1UZ application.

I think we as a 1UZ community are still missing comprehensive data on modding these cars. Possibly because there are such few aftermaket parts for these cars, people end up making their own, which is different from a company designing and flow testing and developing for a customer base. If you go to HKS and ask for some 2JZ parts, you will get the flow data and have a known path with known expectations. This is far less true n the 1UZ market. Which is a little surprising.

 

[JustenGT8]

From what I understand with FI it doesn't really matter so much, much like exhaust design for FI, just make it large and not have an restrictions in the flow. Feel free to flame me if I am wrong

But what about the capacity and what not? I know there is a lot of complicated stuff like pressure and whether or not all cylinders are getting the same amount of air.

No call for flames but don't dismiss FI design...for either inlet or exhaust. Pretty well any exhaust design down to a simple log manifold will seemingly produce good enough results but a well thought out design for the application will still produce much better results eg short, thick wall runners for street use and reduced total length over equal length in design. For track then longer equal length is the go as you are operating in the higher rpm range. The 1st is targeting low/mid range response the latter peak hp.

Same for inlet. While peak flow is needed for peak hp, factors like intake velocity, cyl distribution etc will determine driveability thru the whole rpm range. Increasing area under the torque curve is what most of us are trying to achieve in reality as that will give the best performing street car.

If you need a new plenum because of packaging issues such as my mate with the TUZ in a 75 Celica then a coupla basics to aim for. Plenum size at least 1.5 x engine capacity which helps smooth out individual cyl pulses. Use bellmouths with the appropriate radius and rather than have them proud in the manifold have the bellmouths flush against a backing plate. If it's space issues causing the need then you are gonna be challenged regardless i suspect.

Yes you can use ITB with FI but getting a good vac reference for many ECUs can be a problem. The Nissan GTiR used these to good effect as does the GTR but they are a rarer beast than the single throttle and i would question the bang for buck in a custom setup.....great bling factor though

 

[ed_ma61]

id suggest reading these. save your breath here

http://www.toymods.net/forums/showthread.php?t=12801

http://www.toymods.net/forums/showthread.php?t=6525

http://www.toymods.net/forums/showthread.php?t=7600

 

[LondonBenji]

Wow, cheers mate, I got lost reading through them all and where they were linking elsewhere!

Also I have been reading your v-eight stuff, very interesting stuff which usually goes way over my head, thanks for the info.

 

[ed_ma61]

itll sink-in eventually - just keep reading

 

[LondonBenji]

Basically from what I gather it seems that the same tuning principles for NA in this area will have an effect and help squeeze that extra little bit out, but it has less of an effect or seems to be 'less important' when going FI. Would that be fair to say?

Interestingly from another thread I found these pictures:

http://www.monsterhorsepower.com/movies_pictures/tte/pictures/

Given that TTE (Toyota) would probably know what they are doing it is interesting that the intake plenum here looks very similar in design to JDMFantasy's new design for an intake plenum:

JDMFantasy -

TTE:

 

[ed_ma61]

id be tempted to say that the TTE item is a WA intercooler... as far as 'plenums' go that a pretty crappy design

your general take on NA vs FI plenums is correct. but theres more to consider (always is)...

http://www.v-eight.com/tech_forum/viewtopic.php?t=268

http://www.v-eight.com/tech_forum/viewtopic.php?t=250&start=0

http://www.v-eight.com/tech_forum/viewtopic.php?t=269

 

[LondonBenji]

Brain........melting....... :684:


Cheers dude, by WA I assume you mean Water-Air?

 

[JustenGT8]

Pretty sure Ed is on the money there with the a/w IC call....it's also a design constarined by packaging as not much room to do anything else and still fit the SC in there too.

 

[LondonBenji]

Why is it a crappy design though? What about it makes it bad?

a/w IC's seem to be able to disapate (sp?) huge amounts of heat very will but from what I have heard they are not good for continues high load situations but more for drag strips or short bursts...?

 

[JustenGT8]

a/w have their place but in most cases a good FMIC is more efficient, easier, lighter and cheaper. For tightly packaged SCs the a/w can be a good option.

I'm using a/w on my latest proj but for reasons of stealth rather than any performance requirement.

For that TTE setup i would have said the manifold was fine...for ultimate perf though, perhaps not, dunno without testing?

 

[LondonBenji]

Interesting, from what I read a/w is extremely efficient at extracting the heat and shoving it in the water but then once you reach the 'heat capacity' of the water that was it, hence why its good for drag races or short bursts of power but not continuous load.

Effectively you've got as much heat capacity as you have water in your system and how good your additional water radiator is at extracting the heat from the water again.....

Is there such a thing as a hybrid, effectively a/a+w if you catch my drift?

 

[JustenGT8]

Sorta....the new big thing in IC is dry ice. Mostly for drags and dyno queen runs but very effective. Similar deal to a/w, you enclose the IC but instead of water as the heat exchange medium it's frozen CO2. As the dry ice pulls the heat out it gases off so it's a use once type setup.

For 90% of street FI applications a decent FMIC is the go. If you need more cooling again then use water injection as i do

 

[LondonBenji]

Hmm CO2 way sounds cool but not my style for street/racing.

I've done a bit of googling, FMIC correctly set up does seem to be extremely efficient and like you say less weight, less complexity, etc. But, say your using a mid-rear setup, FMIC becomes a difficult option since your going to have lengthy pipes which will cause a pressure drop and thus turbo lag.....

MR setups have heat issues as it is being in the back and not the front. What would be sweet would be to have air ducts like ferrari's and what not directly blasting on to the intercoolers loosing heat to air that way but then at the same time transfering the heat into water and sending that up long pipes to big radiators up the front, since long pipes just means more water and thus 'heat capacity', it's almost a win win situation.

Or am I barking up the wrong tree here?

 

[JDMfantasy]

I think we as a 1UZ community are still missing comprehensive data on modding these cars. Possibly because there are such few aftermaket parts for these cars, people end up making their own, which is different from a company designing and flow testing and developing for a customer base. If you go to HKS and ask for some 2JZ parts, you will get the flow data and have a known path with known expectations. This is far less true n the 1UZ market. Which is a little surprising.

Our manfiold was proven to flow just under 30% more air to each cylinder compared to stock (2UZ that is). Cfm per runner was increased to around 265, up from the stock numbers of around 215. The variance per runner was also less with our manifold. Testing was done using the commonly accepted 28" of water, at only 4500 rpm. Most of these manifolds will see anywhere from 6500 to 8500 rpm, where they'll really shine.