I’m scanning the archives but it’s hard to find what I’m looking for.
I have a stock VHPD engine (Elise, not Exige), brand new this year, completely original bar piper verniers which have been correctly set. The exhaust manifold is a tubular 4-2-1 which I think is stock Lotus and exhaust is the Janspeed Exige (inlet and exhaust on the same end of the silencer, single outlet pipe). I use the car for a little racing but also on the road: if at all possible I want to keep emissions legal (with the original Lotus ECU, plug swap the ECU for racing).
I will shortly put it on rollers at Dennis Vessey (I use a Lumenition GEMS ECU and he knows that ECU well) but wondered what BOLT ON options I have. At the moment the engine is dead at 3k (probably a fault in the Lotus map), comes alive at 4k up to 6.5k but seems to lack urgency beyond that. Some of that is map, some induction, I’m also suspicious of that Janspeed exhaust.
I guess I could change cams but I am limited on options with the engine in the car (doesn’t the head need machining to take 1444s?). The standard throttle bodies are perfectly fine in my view, although longer trumpets may help. The exhaust manifold looks fine to me, although possibly someone may have measured whether a more highly developed 4-2-1 yields benefits.
Given that I have no budget or inclination to rebuild the bottom end yet, and would like to have the road legal option, what is the best way to go now? I am sure the remap will do a lot to tidy up below 4k and exploit what potential there is up to 7500 or so, but there could be a killer gotcha in there somewhere that makes all the difference.
Before you ask, yes, when the bottom end comes up for refresh I will get it properly blue printed, have the head fully ported and dyno test the lot. I “redline” at 7500 for now.