Quote:
Originally Posted by Derek UK
On paper the Stromberg apparently has a higher flow rate but for performance it is usual to swap them out with SU's. Emissions was the main reason for the change to Stromberg's.
Knife edging etc is for top end and probably only measurable on a dyno. Having a set of short medium and long trumpets might confirm some ideas but needle selection probably the key issue. Are Stromberg needles readily available at a tuners? Filing is a black art and you never really know what you end up with. Dyno time is expensive unless it's being done on a friendly basis!
Don't forget to fiddle with the timing.
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Thanks Derek. The Stromberg has a smaller stepped area directly after the bridge so there is potential for extra flow but the casting is pretty thin.
I have a stub stack with a K&N filter fitted inside the original housing, it definitely flowed more and became too lean with the B1CC needle. I did a spreadsheet with all of the needles available and did a graph and showed three best choices with the best of those being the B1AN needle. It is one of the richest needles. I test ran it with my O2 wideband sensor and it was spot on. The dyno guy also said it was spot on, a little rich at max revs was all. The dyno came in at 90Hp (76.4hp at the wheels) so a pretty conservative conversion. That could be a increase of 8 or more Hp compared to stock so if correct a good result. The car goes lovely. Not sure when I will get round to modifying a carb, I would like to just see what difference it makes. There aren't many richer needles to chose from so won't be straight forward.