Quote:
Originally Posted by gsxr
Not me, but a couple people over on the STD forum (?) put a 3.5 pump in a 3.0 and said it made more low-end power. The 3.5 pump is calibrated for less fuel up top though (especially the .970) so I never had much interest in playing with one..
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I understand the same, someone here was running one in an '87 300D and said the same thing about improved low-end power, but had noticed nothing about the high-end. However, since the .970 had a reduced high-idle setting (by 250rpm IIRC) it would make sense that the pump high-idle would have to be increased to match that of a .96x pump for a true comparison (an easy adjustment). Other than that, it makes sense (to me anyway) that the .970 pump would need a higher injection rate (faster rise of the cam) for better emissions (accomplished without the trap-cat on the .97x) I would
assume, ... I'd like to know how it differs though. Did the Bosch book give fuel numbers for this pump also?
Quote:
Originally Posted by gsxr
If you watch carefully, the EGT's seem to be fairly stable when boost is near 20psi, but then climb rapidly as boost drops to 15psi. Could be coincidence though. (?)
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I didn't notice this, odd.
Quote:
Originally Posted by gsxr
I was never convinced that the .97x pumps were the way to more power, and the fact that Myna would charge extra to replace the .97x cam with a .96x cam seemed to at least somewhat corroborate that.
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Although it is possible that there is a down-side to the later pump's cam, it is also IMO very likely that the development of the Myna elements was done with the early cam profile, and is thus matched to it, ... not to the other cam(s) so that's what is required. The 603.96x IP is probably the most common mechanical 6-hole Mercedes pump also, so I can understand why it was used for the development of the Myna pump/elements.
If I'm correct in this assumption, then there is no correlation between the 606t 6mm elements and the .96x IP cam, it is a only a guess whether they would perform as well (or better) in a .970 IP. BTW, I'll be happy to send you a good .970 IP to play with provided it comes back in its original condition.
Do you know if a 606na manifold will fit a 603 head? It seems that if it would, it would make a great starting point for intercooling a 603 so that you don't have to deal with all of the fabrication on the (dismal) 603t intake manifold/plenum.