Ive decided i want to go ahead on a TWM intake for my current pp rebuild.

the motor was previously ran with a 51ida and rx8 internals, i wasnt fully convinced i could the most out of this setup and i wanted to move on from carbon apex's so we're rebuilding it going with efi and Lightened S5 n/a rotors with nrs ceramics.

The motor has a large short primary header (around 25"from memory), we plan to run it to just to under 10k.

- low rpm power / running isnt too much of a concern. as car will not take to any daily driving, mainly open roads or track days.
- pp intake is 50mm, and square ports with exhaust sleeves removed.

now, i dont want to go with efi-hardware/tweak it etc itbs, as they're relatively common down these parts and i like to try different things.

TWM make 56 / 58 / 62mm sizes.

Im having a hard time deciding which to go for.. Is it possible to "oversize" on pp motor and giving it too much air?

I understead air intake velocitys slowing down with the larger intakes, but makes up for it in the upper rev range.. for eg. If i went for the 62, will i need to pull even larger revers over 10k to work most efficiently?

any input will be greatly appreciated

 

i didn't realize there was a 56 mm (unless that's a typo), but i, personally, wouldn't go over 55 mm (or 56) for what it sounds like you're planning.

if i understand the correlation between larger bores and powerbands, i'd say there is a limit to what you'd want to install. i don't think the size matters so much for drag racing, where you're pretty much going all out most of the time. however, if you're doing road courses, i think larger throttles tend to decrease your ability to modulate throttle inputs between fully open and fully closed. think more of an on/off switch versus a rheostat.

i hope this is not misinformation, but if it is, i'm pretty sure it will be corrected.

 

the ONLY thing i can tell you is that the MFR PP setup, is a 48ida and the runners taper down (on a 12a) to about 44mm...

so if you had 50mm runners, 55,56 looks nice...

the CARB people run 58 gene berg IDA's, but those have a venturi, so it isn't quite apples to apples

 

http://www.twminduction.com/Throttle...eBody3002.html
yep they make a 56.


Ok, at this stage looks like 62mm is out of the question.

From searching various forums. including this one, (mainly about genebergs 58s and terminators) people say "YEa rotarys love as much as air as you can cram down there!"

or there was a post somewhere, i t might even be on the twm site somewhere about the their intakes not using tapered bored, their reasoning was that EFI iand proper tuning can override the effects of a venturi as on a carburettor.

I find havent been able to find anyone who personally runs the newer twm setup... Surely they must sell quite a few otherwise it wouldnt be economical to manufacture.. or perhaps people running these setups are at the top of the game, and not interested in revealing?

 

I've seen more than one 13b pp with a Gene Berg 58mm IDA copy with 48mm chokes work dam well on the road course.

56mm is looking good.

 

cool at the moment, i'm considering the 58 as a compromise between drag power and track driveability.

however i have no science to back this up, so it will purely a hunch from what people have said