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Re: Two barrel TBI must have a flaw, I give up.



Dun run 13s with a cross fire (84 Firebird) (admittedly lots more tuning,
experimenting then ya'll did).   Shifted at 5,500 to 5,800 rpm (cause it was
to last long term).  Dun splained it in tuning docs., and various postings
Grumpy


> I dont know exactly, but I think it has to do with fuel flow and puddling
at
> the bottom of the manifold
>
> I just did a s--tload of testing and was as methodical as pablo gets..
> issuming I was going lean I started off with 20 psi, and just increased
the
> pressure in like 3 psi increments.. there was a point where it had gotten
> slightly better at the top, my test was in first gear starting at 3500 rpm
> the drop in power occured always at the same rpm but at differening
severity
> somewhere slightly above 30 psi yeilded the least severe drop (very very
> mild improvement if at all) but severe nonetheless (did not pull past 5000
> much).. as i increased pressure from there i was greeted with diminishing
> returns.. there was NO possible way I was going lean, my BPW was set at
134,
> and I was at around 90% ve wot at high rpm, 65 lb injectors (yellow/brown)
> as i increased the pressure still further. the problem became worse. It
was
> very very bad the higher it went. I believe the same problem a carburetor
> has at high rpm, the TBI has, only worse since the fuel is injected at a
> higher pressure, that is the fuel hits the bottom of the manifold and
turns
> into little streams.
> This is all just hypothesis though, I have no other way to explain my
total
> lack of high rpm horsepower
>         Perhaps a much lower pressure would remedy the situation.. i dont
> know.. the only problem is that a lower pressure would also yield less
fuel,
> at 19 psi these injectors would only support 300 hp
>
> Unless anyone here has had any good luck with two barrel tbi setups at the
> high rpm end of the spectrum and can tell me anything ground breaking I
> think this battle is lost.
>
>
> Pablo
>
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