frog

Silly question time probably

Say you're going on a slight uphill and pulling 2k rpm in fifth, accelerating slightly, while the engine isn't struggling, it feels like it works hard pulling the car, more throttle gives no better acceleration.

Could this increase the likelyhood of damage to the engine ?

Reason I ask is that I had a R5 years ago that detonated badly under load after the h/g blew up and was replaced (not using that garage ever again!), dropping gears appeared to make the detonation disappear (maybe cos I couldn't hear it any more )...

So, I was wondering if similar driving conditions for a good engine would increase the likelyhood of detonation, especially in hot weather with equally higher ACTs.

bud-weis

i wondered about this too, and i'm not sure how you'd avoid it with the mapping, but as you say when the car is struggling and you apply more throttle,nothing really happens....so i'd imagine your dumping loads of fuel in for no reason??

obviously changing down a gear is the solution but i'm unsure as to any damage,would expect it to be overfuelling big time whilst on say 90% throttle and only 1-2 or very low psi..

AndyRST

You arent dumping anymore fuel in at all. The car only fuels for the air its flowing

bud-weis

but how do people map cossies, is it throttle angle and MAP they go off??

the ecu won't know for sure what air is flowing,but i guess there must be a point in the map for 90% throttle and 2psi .......??

foreigneRS

as said, you'll only put more fuel in if the load seen by the MAP sensor increases and the map has more fuel at that point and / or the load seen by the TPS as a transient input puts more fuel in.

would only cause damage through det if the combination of too much ignition advance, AFR, in cyl temp, fuel octane etc is right

AndyRST

Isnt that why most modern engines have mass air flow sensors. Dont know about cossie engines tho.

GARETH T

your car was badly setup


no on a correctly setup car

swing


the ecu is mapped, speed (engine rpm) density (manifold pressure, and air temp) and throtle angle (i bet you guessed that one )

Csm

Ive heard it can be just as rough on the engine as is hard revs if not worse for it

just what ive heard tho

reality

On a properly mapped car you can nail it in 5th from 1000rpm all the way to the red line on a blisteringly hot day and not melt it.. this is the greatest load it'll see on the road (well, apart from going up a steep hill, but the same test should apply)..

bud-weis

The more i think about it the more it makes sense

defo had cars before where i floored it in fifth,and it just felt like it was gonna pop! (in fact it did in a series 2 turbo i had )

i have also seen cars chuck out loads of black/grey smoke when booting it at low revs in a high gear, is this down to bad mapping then??? or this transient fuelling whatsit i know nothing about

reality

bud.. bad mapping/bad setup/something wrong

Stu @ M Developments

iTrader: (12)

Correct. No other options.

frog

Ok, sounds like it wasn't such a silly question in the end

I know, the head/block were skimmed too much and the end result was a gutless engine that "pinked" all the time.
A common problem on R5's after a h/g change apparently

So, as long as the car is properly mapped, there is no adverse effect other than you're going nowhere fast and should drop a gear or two along with the pipe and slippers

Jay,

iTrader: (4)

i tend to left foot brake while accelerating up up hill to whilst mapping to create exstensive load