i posted a suggestion on a members N/A FC build asking if he had considered a 48mm ida for his 6 port. Is this something only done in NZ or something coz he replied with a disgusted "are you serious" I'm not offended by it just wonder if this is a common view shared by rx7club's users

 

For those not in the know this is what i mean
By benfarnath at 2011-07-14
http://www.youtube.com/watch?v=WClM1-ux32k

they come as injected too


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Mad Mike Whiddett's 26b pp with twin ida's



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In an FB, sure, but I'm not a fan of carb'd FCs.

 

there are efi ida's.

 

I'm rocking a set of DCOE-style side-draft ITB's on my bridged n/a 13B-RE, works awesome for throttle response, especially with the ram air box off of the TII hood scoop. Not sure why so many people hate on them, they work awesome, especially when the stock VDI intake is about 3 times the runner length I need for my port timing. The only thing I'm contemplating now is possibly running a variable length air horn a'la the R26B intake setup on the 787B, especially as I could do it through the Haltech E11v2 I'm running as a function of RPM through a 3 position servo or something of the sort, but who knows yet...

 

sounds cool got any pics of your engine bay. yea the trumpet intakes like on the 787b are mean like on mad mikes first setup when he had the 3 rotor in his fd ? http://img140.imageshack.us/img140/4418/dsc011940fv.jpg

 

Kinda, the 787b intake runners would change length to help the torque curve, along with a telescopic intake duct that what close at higher speeds to reduce drag, which incidentally were banned in 92 i think.
But on topic, i think people just dont know how to tune ida's anymore. Ive done one in a old datsun and some older formula mazda cars, but havent seen many in fc's. I think everybody just goes turbo for the most part in fc's while in alot of swapped cars receive the ida or itb set-up (miata's, datsuns, etc.) but i did say "i think" alot so i could be wrong

 

I think the carb. association is probably what turns people away from the idea..
And for stock ported people, an S5 intake is probably best.

That injected intake looks pretty awesome though..

 

*Disclaimer: I am not a fan of carb's but I enjoy the discussion*
Those examples of IDA's are awesome, but I think are a very niche part of the market, especially on FC's. I think Derekcat nailed it on the head with the carb/IDA association. In general, a turbo is simpler and cheaper solution because the path is well laid out.

For Carb IDA's: If you have to suggest it to someone, they are probably not going to have the expertise to get it/keep it running well. It seems to me, it's a lot of work and money to convert from EFI for relatively small gains.

EFI Carb's: A standalone EMS would be needed to use the IDA's potential. Again, most people (and many shops) don't have the expertise to do it well. If it comes down to spending money on an 300 hp NA IDA intake vs a 400hp hybrid turbo setup, I think most people woul go turbo.

 

Good point on the carburetor/ida association. For some reason NZ has a rather large affinity for 'em and have the tuners to sort them out. I think it would work out cheaper going the ida route as opposed to a serious turbo but only marginally so i see why you would go turbo. Just think if you have an NA and wanted to port it and stay NA then efi ida would be a really good way to go. And they sound sexy as!

 

i wonder if NZ they have done the math and found the s4/5 TB intake is larger than even the EFI weber TB 55 mm specials
and has staged throttles to boot

the only thing the weber manifold has over the stock inlet manifolds is short runners which may suit heavily modified ports a little better

for the majority with mild ports there is nothing to gain ,, and something to lose in swapping down to a weber TB and manifold


that said,, in the early rx's,, which have poor carb and manifold choices,, the weber reigns supreme and i do love the webers i have owned
and i do love the simple joy they are to set up and tune for others ,, holley = fail whale

 

I didnt realise but to be fair no one really rocks around NZ with an NA with anything less than a half bridge. I'm sure some do but thats only while they save up to get it done haha (with the exception of an rx8 or standard car purists of course)

 

I'll he rocking the tweakit.net throttle bodies by the end of the summer on my full bridge build. Starting asse

 

stock FD- 45mm x 1 + ( 50mm x 2 )
3.14 x ( 22.5 x 22.5 ) = 1590 mm2
+
[ 3.14 x ( 25 x 25 ) x 2 ] = 3926mm2
= 5516 mm2 staged throttle body, 1 x 45mm, 2 x 50mm


stock FC- 45 mm x 3
3.14 x ( 22.5 x 22.5 ) = 1590 mm2 each
1590 x 3
= 4770 mm2 staged throttle body, 3 x 45 mm
( s4 and s5 rx7, NA and turbo )

weber type TB 55 mm
3,14 ( 27.5 x 27.5 )
= 2375 mm2 each
2375 x 2
= 4750 mm2 2 x 55mm
( weber type efi TB )
compare the weber 55 TB and the stock unit !!!!!!
( some brands taper down to 50 at flange !!! )

weber type TB 50 mm
3.14 ( 25 x 25 )
= 1963 mm2 each
1963 x 2
= 3926 mm2 2 x 50mm

60mm x 1
( holden VN v6, toyota 7M , 1JZE-GTE, nissan RB20 , SR20. liberty 2 and 2.2 )
3.14 x ( 30 x 30 )
= 2826mm2 single 60mm TB


weber , 42 mm chokes
3.14 x ( 21 x 21 )= 1385 mm2 each
1385 x 2
= 2770 mm2 2 x 42 mm choke weber

weber , 37 mm chokes
3.14 x ( 18.5 x 18.5 )= 1075 mm2 each
1075 x 2
= 2150 mm2 2 x 37 mm choke weber


dont get me wrong,, mazda made manifolds as compromises for space and for helping to fill the down low hole suit grandma rather than please boy racers up top

myself have proven even the 60 mm holden TB is no hold back on a boosted rotor at around 1 bar and still gets better than anticipated results
that experiment included revised plenum volume and using only the LIM runners
and also indicated the mazda manifold runs flat up top, as the short runner big plenum got a second wind there
( but was rather flat below 2500 rpm,,and that is mazda's point )

so i do understand maybe a little why some builders in NZ may lean that way
( not to forget asthetics and also extra parts sales )