I just took my car to our local track and car didn,t run the times i thought it should esp.w/tune and 1.6 rockers! I realized that i still had the BBK 52 mm gasket on my stk 48 tb,a tear in my intake elbow,and a alt.that had a loose bolt at the back(prob not tightened when rockers installed).I,m wondering just how much these problems affected me? I have put on the correct tb gskt, siliconed the elbow,and tightened the bolt on alt(now battery shows better volts) and will be professionally cleaning the injectors(done 2 years ago)Also my Scanmaster is showing i,m using 28-30 percent throttle went going up a large hill and this doesn,t make sense as the tune /rockers should use less % throttle

 

The gasket won't make difference at all. It really doesn't matter whether the gasket matches the TB @ 48mm or the manifold at 52mm. Weak system voltage will affect it more, reducing fuel pump capacity and requiring the injectors to work harder. The tear in the intake elbow is a major problem. All that air bypassing the MAF sensor at WOT is not necessarily going to result in the correct A/F ratio. Depends how much air was leaking through the tear in closed loop, and how much headroom there was in the long term fuel corrections to cure the problem. Why not replace the elbow rather than try and patch it? Silicon compounds are not good for you O2 sensors.

Sounds like a little bit of mantenance before going to the track might be a good idea.

 

loose boot.

it's called pirate air. air leaking past the maf, not read correctly, and not enough fuel entered the engine

just a BTW for ya...i bought a stock GM TB gasket and used it with a ported TB. the stock opening for the tb on the manifold is 52mm X 2...

your gasket had nothing to do with it....neither did your alternator. unless you were under regular voltage.


scanmaster just takes the % of throttle you're putting towards the floor, off the TPS. that's all. wether or not your engine was using a 30% LOAD or not is determined by what accessories you had, weight of the vehicle, tires, gears, trans, and tons of other stuff. common sense would dictate that bigger engine would need less throttle, but...if you're not geared properly or you had the AC on would make a ton of difference on the load of the engine. even your alternator kicking in at that particular time would hurt power. high humidity, high temps outside, low tire pressure.......too much to dictate

 

Yes my volts were around 12.6 and now they are 13.2,back to where they were before the rocker install.Interesting you mentioned the tires needing more throttle seeing they are 255 dia. vs the o.e 245.I will be going back to 245 and just using the ET STREET RADIALS @the track.The car showed marked improvement just fixing the alt.and the elbow and cleaning the injectors(thru the rail),tires will restore things.Thanks for the replies.

 

by increasing the tires size from 245/50/16 to 255/50/16 you have decreased your gear ratio....with this in mind, full out race cars will increase drag radial sizes to compensate for a limit in gear ratio, or will just go bigger until traction is gained. you can also move faster with the bigger tires with a same gear ratio...but you'll lack ultimate power.

you had a 4% decrease in gear ratio by increasing the tire size. rolling diameter of the 245 series was 80.57" and the 255 was 81.64. you gained 12.64 revolutions per mile...and your speedo was 1mph high at 65mph.

 

Check your math. Using the tire sizes, the circumference of the tires based on theoretical dimensions went from 80.57" to 81.81", which is a 1.53% equivalent change in rear axle ratio. Not likely to be perceptible SOTP.