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I fully agree with this, but I think the main point above is not to let it idle much while breaking it in, especially with a bad tune where over-rich conditions are bad for engine health.
Gotca, I wouldn't run any engine the tune was that bad off on though lol
If it’s a closed loop tune, even a decent one will run at 14.7 AF once up to 100 degrees or so coolant temp.
Ditto for part throttle.
This assumes the O2 sensors are working.
Modern cylinder bore finishes and modern rings break in very quickly.
Thanks I will, I wont be trying to run it in anymore till its tuned
Re other subject, cars idle once warm no problem with no adverse long term effect is agreed, question is do they idle when cold with less harm to the engine than driving gently, I thought the idle mixture was rich when engine is cold? Isn't auto start for comfort of passengers ie heater in cold weather or perhaps turbo vehicles that might derive more benefit from it?
Engine cold vs warm is important that's why taxis can do 500,000 plus miles. I'd say how it's treated when cold makes a much greater difference to the life of the engine than how hard it is driven once it's warm for most. There are uneven expansion rates.
Whatever one decides be nice to it when it's not at operating temp.
Thanks I will, I wont be trying to run it in anymore till its tuned
Re other subject, cars idle once warm no problem with no adverse long term effect is agreed, question is do they idle when cold with less harm to the engine than driving gently, I thought the idle mixture was rich when engine is cold? Isn't auto start for comfort of passengers ie heater in cold weather or perhaps turbo vehicles that might derive more benefit from it?
Engine cold vs warm is important that's why taxis can do 500,000 plus miles. I'd say how it's treated when cold makes a much greater difference to the life of the engine than how hard it is driven once it's warm for most. There are uneven expansion rates.
Whatever one decides be nice to it when it's not at operating temp.
That's hard to answer as there are a lot of variables (ambient air temp being one of the biggest). I would say there is greater ring wear if you let the car idle excessively versus driving gently. I use a remote start on all of my cars all the time. However I don't let the car idle to the point where it reaches full operating temp, nor do I let it idle for the full runtime. I usually hit it as I'm putting my shoes/jacket on, and by the time I get out to my car and start driving, it's been maybe 2-3 minutes. Just enough time to make sure that oil has pumped throughout the motor and there's heat beginning to build in the motor. Like I said in my previous post, excessive idling when cold can wash the bores to the point where ring wear will occur, but short term idling IMO is better so you aren't having to spin to 2500+ on a cold motor.
Keep in mind one other thing: High-pressure valve springs are more brittle versus stock springs. This isn't a huge issue when warm, but can be when cold.
Here is photo of my car and engine its a debadged 99 VT series 2 SS 6 spd the first year we imported the LS engine into an Australian produced car. With 97,000 original miles on it.
Thanks, I will I'm expecting about 370 to 380 rwhp, I made 356 with other cam, it felt incredibly powerful to me at that hp. Some people break the magic 400 HP with baby cams but they are the lucky ones.
Yes it looks a v6 sleeper, yes standard tyres but at least there cheaper to replace if I do loose traction.
I had it tuned today, it drives lovely now with the 6 spd manual it made 279 rwkw (in Aussie Kilowatts equals 374 HP) at 5800 rpm with my small cam. I'm very happy with the way it feels driving.
Engine still only has about 2 hours run time on it since rebuild.
I gained 17.5 HP over last similar cam but I suspect most if not all the gain is not the new engine or cam change but mild head porting with .040" removed from exhaust runners and smoothing shaping of area around seats.
Im curious if anybody knows what the little dip down in torque is around 2500 rpm?
Took it to the tuner today and I drove while he scanned, drove for 45 mins, I am confident he is a good tuner, but on way home I had to take it out of gear to stop it surging, it's only really an issue at 1700 rpm in 5th at 50 mph, trouble is that is the revs I have to cruise at to and from work, I can downchange to 4th to cruise and that fixes the surging but it increases my fuel consumption about about 15% due to a 30% increase in throttle possition (checked via obd port
Strangely it cruises nicely with no surging at 60 mph at 1500rpm in 6th just won't cruise in 5th at 1700 rpm right where I need it to most. I've had injector upgrade and small increase in compression with recent dyno tune.
Is this normal for a cam like this?
217/228 110 LSA .590 lift ?
When I say surge I mean it shakes the drive train back and forth, it starts with just a little and then gets progressively worse unless I take my foot off and re apply throttle gently to correct it, the trouble is a mile down the highway it will do the same again needing correcting again, I cant use cruise control at 50 mph 80 kph.
Tuner suggested I drive in 4th a 50 mph but that comes with a considerable fuel penalty. Same tuner tuned my old cam BTR 219/224 113 LSA and it would cruise on 50 mph no problem.
He can tune that out, your cams not huge... Im just swapping out a 259/265 cam now and tht didnt have surge, couldnt cruise at 100kmh tho, diff gears to long
Get him to fix it
Thanks I better give him a call, I drove for an hour after he road tuned it today to see if cruising in 4th at 80 kph was realistic rather that 5th, you can see my rpms difference and throttle position went 7.06% to 11.76% from my OBDII bluetooth phone app it told be I'd use 2 litres per 100 ks more (note trip kpl not accurate)
It will cruise smoothly with no surge at a very low 1150 rpm in 6th gear at 50 mph (80kph) but I thought perhaps that would be bad for the engine (re: 1150 rpm) just not in 5th.
05-27-2020, 04:42 PM
