View Full Version : Running in And AFR ??
New poster! (less than 10 posts)
My car is now back on the road and been getting run-in , i have clocked up 150 miles and everything so far seems ok ....... everyone had different opinions on how long i should run in it for ...
i think im gonna start running some boost on it , gonna try to set it up for 14psi at the moment with the present turbo , take it too 1000 miles before i put the GT28r on , what afr should i be aiming for ........ 11.8 to 12.0 ........ is that about right ???
As its only in it running in phase i think im just gonna change the main jet ...... do you think a 130 main will be too big ...... ??
I drove mine for cca. 800 miles on standard boost and changed oil and oil filter. After that I started to raise boost and change jets. AFR is good up to 13. Avoid city traffic and do not keep it at high revs and maximum boost more than 20 seconds.
I think that you can leave the main jet as it is for 14 psi since you shouldn't (if you ask me) be hard on gas pedal for running-in period.
Matt Cole
20-10-2008, 22:25
I dont see the need to 'run it in'. If it works it works. I've never ran mine in, infact it got its first outing reved to death on the rollers. Re set tappets changed oil and the engine ran nearly 200bhp for 2 years trouble free and 1 x cadwell tackday and then the engine ended up in a clio running low 14's and 40 plus runs at pod!! Im proud of that lump.:)
If he changed camshaft and following stuff, I think reving won't be healthy.
Rob@Backyardracing
20-10-2008, 22:51
Never ran a camshaft in before :scared:... the only thing i run in is new pistons and liners for about 100miles.... but i dont like new pistons.. Nice older ones for me...:) with new rings of course...:agree:
Matt Cole
20-10-2008, 22:55
If he changed camshaft and following stuff, I think reving won't be healthy.
Damage to the cam is done in the first 20 minutes, after that if its too far gone its gone! The metallic deposits end up as 'hotspots' on the lobes. Driving like miss daisy wont make any difference. If it was me i would get the initial warm up and cool down out of the way, torque head and change oil. Drive it as normal with full boost.
Yeah, that was what I wanted to say about the cam. I do not re-torque the head...
New poster! (less than 10 posts)
Its all new stuff that has gone in , new forged pistons , new liners , new kent rt150 cam. The cam was run in initally , 20 mins at about 2000 - 2500 rpm as i was told to do ..... oil & filter was changed before i hit the road. You can see everyone has a different way of running the engine in so ill just see how things progress as i turn the boost up.
I have never re-torqued my heads in the past either.
When the bigger turbo goes on , what is the optimum AFR at WOT i should be trying to achieve ??? And what afr is considerd to be dangerously lean ???
Personally I'd turn the boost up slightly and start giving it some harder driving. You've done exactly what I would have done after the initial start-up. The only other thing I'd do is re-torque the head and maybe check the tappets again.
Aim for no leaner that 12.5 at WOT I'd say.
Once you've done all that nip round to my house for a cuppa and take me for a spin! ;)
Ok been for a quick blast today and running about 15psi .... still on a 120 main jet , it seems to be fuelling at about 13.3 AFR .... too lean ...at full blast in 5th gear , but on about 60% throttle making 10psi boost its running well lean ....... mid 15s ... is this dangerously lean at that kinda boost and throttle ....or should i not be overly concerned and just look at running correct AFR at WOT ......??
Im running a brand new carb , with all standard jets.
Alex , once i have finished messing around , ill call round for that drink :) .
So 12.5 is the highest figure for WOT then .......?
Andrew Cooke
21-10-2008, 18:05
are you measuring boost at the manifold? If so 15's at 10psi is lean, you could do with nearer 13. You need to measure boost at the AEI line when looking at fuelling.
Matt Cole
21-10-2008, 23:00
......and dependant on correct boost level i would be aiming for slightly richer than 12.5. I wouldnt bother changing the main, stick with the second stage.
the AFR on my turbo 2 is about 12.9-13.1 WOT, just gotta work out how to richen it up.....without screwing up the mid range fuelling...
The boost level figure is carb top , will change that tommorrow and have a look at what it reads at manifold....... and see how that affects things :)
OK i plumbed the gauge into the aei line ..... and i now am recording peak boost of 11psi , reading over 13s on the afr at WOT..... its running very lean on part throttle too ......... 15-16 at some points ..... can a lean mixture cause misfiring when suddenly opening the throttle ????
Andrew Cooke
22-10-2008, 17:46
OK i plumbed the gauge into the aei line ..... and i now am recording peak boost of 11psi , reading over 13s on the afr at WOT..... its running very lean on part throttle too ......... 15-16 at some points ..... can a lean mixture cause misfiring when suddenly opening the throttle ????
15-16 part throttle is fine as long as the car isn't stuttering - that's where you get the economy.
the AFR on my turbo 2 is about 12.9-13.1 WOT, just gotta work out how to richen it up.....without screwing up the mid range fuelling...
im sure i was told a porshe 928 metering head is an upgrade,not sure how it works as i havent a clue with k-jetronic
its does feel like its stuttering slightly ....... but sometimes i get a lot of stuttering when i floor it from part throttle ........havent had proper chance to look at gauge when this is happening ...... does seem like its leaning out ...... will have to take carb off and have a look at it and then consider if i feel i am able to drill the second stage ...maybe to 1.2 .... ??
Matt Cole
22-10-2008, 22:59
you may find that having it a little lean on part throttle is a blessing as i have had 4 carbs all go too rich at that point, normally before boost comes in. As Andy said its a benefit and better for MPG. You dont want it going lean when on boost si i wouldnt worry. Stuttering etc could be carb related and i normally find things improve as you get a few miles on her, almost like the carb settles itself in, probabbly due to heat and fresh fuel through it.
im sure i was told a porshe 928 metering head is an upgrade,not sure how it works as i havent a clue with k-jetronic
thats for the 'tour de corse' cars.- they use porsche turbo injectors too. the problem is they move all the stuff around to run it, and the flap moves downwards instead of the standard upwards....
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