that's the placebo effect after one has spent shed loads of money on a performance enhancement that doesn't do anything something is wrong with the new set-up, poorer jetting, air restriction in the filters or you're restricting things with your exhaust?. The real measure you should be looking at is the significant drop in torque. the old set-up is generating a nice smooth curve with higher torque at a much lower engine speed and lower road speed. On the second run he's effectively thrashing it, he's taken the RPM right up to the limit and you're achieving a lot less at a much higher RPM and road speed. The curve isn't as smooth either. So either your set-up isn't working or the second guy doesn't know how to set the machine up, but there isn't much he can do wrong and all the figures are there to see. What you want on these buses, as you've said you want to carry about loads of heavy stuff and climb hills, is torque - a good rolling road 'tuners' will be able to tune the engine to what you need, will be experienced with carburetor engines and will be able to rejet it etc. Looks like you're just paying someone for a run on the road, so what are you hoping to achieve? Did you never watch top gear when they spent £000's on an Aventime and ended up with a car that went slower?
Thankfully the modifications cost me the price of an exhaust fitting kit and some fresh fuel lines Yes - I paid £40 purely out of interest to discover what difference these common modifications made. As it turns out, none! The driving experience doesn't tally but I can't argue with the numbers. Just strikes me as odd that I'd expect at least a couple of bhp from the exhaust swap from stock to better flowing quiet pack. I'm cracking on with my beetle then I'll return to the van and have a look at the jetting at some point.
http://thelatebay.com/index.php?threads/rolling-road-results-guess-the-bhp-part-2.27597/ Looks a familiar setup (less 57cc) @Mucka do you know your jet settings etc? Cheers
@Mucka 's initial results (stock) : The results are : 42.2BHP 68.4 lbft 25.5BHP at the wheels and top speed was 75mph max power was at 58mph He did find that the throttle cable was not opening the carb fully so it could of made a bit more power Next results will be after engine mods. Mine was 45.1 BHP 85.4 Ibft 29.1BHP at wheels Mucka's after mods... 60.9 BHP 94.9 Ibft Hmmm..... I know it's a different rolling road etc but both are on the same 'road' before and after.
Something's not right with your "after" results. Mine was 58bhp with crappy Scat Solex copies and a quad Monza exhaust...
I have a monza lurking somewhere in my garage I removed from a friends van for him out of kindness ;-) Hey, I might stick it on! Can't make the results any worse?! Joking aside I agree though @Baysearcher. Especially now I've found @Mucka 's post. Hmmm
Mine was an original Monza, not a tinfoil Empi copy, but it still strangled the hell out of the engine! I reckon they did something daft when they re-ran yours.
don't just read the numbers, look at how its delivering its power too - as i said he's either set things up wrong on the road or it wants rejetting. Randomly changing the jets by guess work will possibly get you somewhere close but if you want it tuned to how you want to use it you'll only achieve this on the rolling road. Your road guys should be pointing you in the right direction. What air cleaners have you got on there, have you got j-tubes, h/x's, exhaust header? I doubt the exhaust will have any influence on this at all so you want to be looking at the carbs. The curves and the figures show that you're creating the same output with much higher engine RPM, basically its taking more effort to get to the same place so something you've done is restricting the engine
Mine was on the engine for at least 9 years and when I sold it complete the exhaust was as solid as the day it was fitted! The Empi ones seem to rust as they come out of the box. Maybe the originals also flowed better but I'm not sure!
Agree about the numbers @Joker. Just doesn't tally with driving experience. You don't need to rev the engine to get the 'power' (if that's what you want to call it!) It pulls from idle etc and drives on light throttle. Vans on heat exchangers/4-1 header and bluebird box. Filters are the stock oval K&N style ones cleaned and reproofed.
I've already contacted him Waiting on him getting back to me. They're are really nice blokes. Had an interesting conversation about tuning, carbs, motor racing and fuel injection yesterday with them.
I'd pop along too if I was off work. Let me know. Would love to see the process. ( on someone else's van first )
