Slowbrick
Mine also doesnt glow with a 15g on a 90+. Maybe LH2.4 runs leaner than LH2.2 on hard driving?
Dauntless
I don't think it runs particularly lean under boost, but don't have a wideband. After a hard run with the 13C I had the whole lot glowing from the runners to the downpipe flange.
Vee_Que
So it glows less then. And Aj as we've discussed before hates being below 3000rpm when driving.
Dauntless
Haha, nah the 740 was happy cruising at 2500 or so.
jamesinc
I ran 2.4 with a wideband. It runs 11-11.5 at 13psi. So not as rich as 2.2 but close.
Philia_Bear
Exhaust moves through the runners at supersonic speeds due to the pressures and waveforms involved
Issues will be around reflections causing harmonics that cause waves to slow or stop in odd points and choke points preventing the mass of exaust moving through without a further increase in pressure which distorts the waveform and causes further reflections
Both designs are pretty poor with the 90+ being slightly better
either way picking a better turbo and other mods will deliver far more improvements for the most of us here or so goes my $.02 of the day
Major Ledfoot
@Philia_Bear and others, what are your thoughts on the design / efficiency of the factory B204FT 16V manifold? Is it worth the trouble of getting one for a 16V +t engine, or would it be better to do a custom?
IIRC Richard Prince ran into issues with it at engine speeds over 6500 RPM, but that was in an Improved Production racer with a rules-required restrictor on the compressor upstream.
Philia_Bear
not worth money to buy the 204ft manifold over just using an adapter and a 90+
16v motor with adapter and 90+ and 19t and E85 would be made of DD win
Tree
So Mr Pbear, to reiterate your 2c, an upgraded turbo + 3 inch turboback should be most bang for buck?
Philia_Bear
Yesm
deleted_user_160
And if your like Alex and myself we have already got the 3" turbo back, and looking for those extra gains and low end increase, this is the next step, less going for a complete tubular manifold.
Vee_Que
I went from a stock exhaust to a 3". It is infinity better, but I've already told you that @tree
Tree
Does turbo back encompass the dump pipe? Actually I don't even know what a dump pipe is lol.
Yes you told me, 3 inch is the go. Quick browse on turbobricks confirms.
In regards to low rpm, when do people shift? Below 2.5k is gutless hesitation. Is this characteristic of 80s turbo car? My previous car was 2.0 16v dohc with vvti (intake side) and I could shift just above 2 without problem bogging down.
I thought 2.3T would build torque lower over 2.0L. Exhaust upgrade will obviously improve
Vee_Que
The head flow on your mr2 was quite a lot higher. Maybe ask about short shifting in another section. Yes 3" from the turbo back, most turbo cars in my experience don't make much power up to 3k, but enough to drive like a granny.
deleted_user_160
So what is the chances we can set up a flow test of factory manifolds, maybe including intake as well
Vee_Que
I have one of each currently.
deleted_user_160
yeah so now just to test. is there melbourne local venues that could test?
maybe even a uni? (because im a tight ass)
jamesinc
Yusss. Oz Volvo, where we TEST OUR THEORIES.
Samman88
If someone would lend me a manifold I could try doing a simulation with NX. It would be far from ideal though as it would rely on my measurements of ports and guestimates of the internal runner dimensions as I do not have access to a 3d CAD scanner. It would come out looking something like this:
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it would be rather non-empirical and error prone though. But food for thought.
BradC
Vacuum cleaner and a MAF ?