793 replies to this topic

[Scuffers]

  was that in testing or at a track day as the fastest ive found for cliffs car was 2:07.4 from looking through TSL timing when they last ran the 300 circuit which was september 2012

Test day before croft round.

[turbotoaster]

plumbed in inlet and outlet for intercooler



also had a go at making some det cans today following instructions online but dont seem to work very well(to quiet) with car idling but when driving they are pretty good actually

i also like this pic, shame he missed the flames

 

well started testing my intercooler setup tonight, i had some hopes for it and while its not quite as cool as i was hoping for its a good start. ambient temp is 15c, so with 13psi of boost flat out in 5th gear(aero limited so holding top speed for 6 seconds) it peaked at 27c, next upped the boost to 19psi and did the same thing(this time 7mph quicker) and peaked at 30c, bare in mind on a 4th gear pull without the cooler i was getting 57c on high boost and still rising.........I would call that a pretty decent result, i may bodge things alot but I always think hard about things before i put the effort in.........the intercooler isnt ducted yet so its only picking up air coming through the engine bay so theres more improvements to be made

[chris_uk]

it might be worth making something like the Mp4-12C has for the intercooler

 

 

 

[Nev]

At what IATs do you start to retard iginition on map please, and by how much?

[turbotoaster]

on mine ive set it up to pull 1 degree at 50c, 2 at 60c 3 at 70c and 4 at 80c

 

With much colder temps i now have i can start putting more timing in at the lower boost levels, just havent got around to doing it yet, on the high boost its 12 degrees of timing as i thought i heard a bit of det at 14 degrees at high rpm, i know i did have some at 22psi spike with 16 degrees as i heard it so pulled some there also.

 

Its not that easy to map ignition on the road with a mid engined car with a turbo behind your head as there is alot of noise so will have to make a few tweaks to improve my det cans but since they only cost me £10 to make they are useful for learning

[Nev]

Gosh, only 16 degrees of advance? That engine must be quite different to our Vaux lumps, as I think my engine advances to about 35 or 40 degrees in various places on the map. How do you know that 1 degree at 50c, 2 at 60c etc is the correct amount, is it just educated guesswork based on not hearing the det under any loadings? Presumably this is how RR mappers would do it too, abeit with a knock sensor on the block and an amplifier and headphones.

Edited by Nev, 27 July 2015 - 05:50 AM.

[stu8v]

Would the number differ dependant on the position of the crank position sensor?

[FLD]

Gosh, only 16 degrees of advance? That engine must be quite different to our Vaux lumps, as I think my engine advances to about 35 or 40 degrees in various places on the map. How do you know that 1 degree at 50c, 2 at 60c etc is the correct amount, is it just educated guesswork based on not hearing the det under any loadings? Presumably this is how RR mappers would do it too, abeit with a knock sensor on the block and an amplifier and headphones.

35 - 40 degrees is lots of advance!  IIRC its the sort of thing you do at really low revs to stop the engine stalling, in reality the engine never actually 'sees' that amount of advance.  (My knowledge is pretty old skool so I may be waaaay off). 

[Bill SC]

Other way round I think...? As crank speed increases, advance increases, it's also relative to throttle position. More fuel in the cylinder the longer the burn time so the more the advance to get the "sweat spot" in terms of utilising the combustion effectively. Will be different on an NA to a charged car as well I would imagine as although the ideal AFR target would be the same, a charged car would be putting more fuel and air into the same space and so burn time would be longer, which needs more advance to effectively utilise the combustion.

Pretty sure My SC runs up somewhere around 40 degrees at full throttle, don't have the table on me to double check though.

 

[FLD]

 

 

[turbotoaster]

Gosh, only 16 degrees of advance? That engine must be quite different to our Vaux lumps, as I think my engine advances to about 35 or 40 degrees in various places on the map. How do you know that 1 degree at 50c, 2 at 60c etc is the correct amount, is it just educated guesswork based on not hearing the det under any loadings? Presumably this is how RR mappers would do it too, abeit with a knock sensor on the block and an amplifier and headphones.

 

On the dyno with the small turbo i was only able to put 17 degrees in at 16psi before reaching the knock limit, now that the temps are lower it might allow for more timing at lower boost levels, ideally need it back on the dyno with the my headphones on as its easier than doing it on the road.

 

The temp correction is an educated guess as the only way i can now simulate the those temps might be on track and i would have to drill and attach ear defenders into my helmet with a tube running to the engine to listen to whats happening.

 

I would of course disconnect the intercooler to run hot inlet temps again and map it on the road like that if so needed

 

yes nev, how much ignition you can add into the timing table is all down to listening to knock and also seeing the torque increases with each degree you put in, if it doesnt increase and theres still no knock there is no need to add it in.

 

Other way round I think...? As crank speed increases, advance increases, it's also relative to throttle position. More fuel in the cylinder the longer the burn time so the more the advance to get the "sweat spot" in terms of utilising the combustion effectively. Will be different on an NA to a charged car as well I would imagine as although the ideal AFR target would be the same, a charged car would be putting more fuel and air into the same space and so burn time would be longer, which needs more advance to effectively utilise the combustion.

Pretty sure My SC runs up somewhere around 40 degrees at full throttle, don't have the table on me to double check though.

 

 

 

you want to run richer afr on a turbo/supercharged engine than an NA engine

 

you can run more ignition timing out of boost and before peak torque but when reaching peak torque you need to pull timing to stop detonation, you can feel a little back after peak torque but not much.

 

I would be very surprised if your running 40 degrees anywhere near peak torque.

 

I also run similar ignition timing but nowhere near boost.

[Bill SC]

Not at all sure about the timing thing but if you ask Chill nicely he might be able to interpret my map to confirm what you are saying above. I wouldn't know how if I could see it.

 

However, ref AFR it's more that inadequate cooling usually means you "have to" run a richer AFR in charged cars in order to manage temps and prevent detonation.

 

Max power/torque etc... from any combustion event is at the same AFR regardless of NA or charged (assuming all other things are equal). Think it's about 12.5 AFR if memory serves but don't hold me to that, a quick google search will clarify.

 

People use richer mixtures in forced induction because forced induction tends to run hotter (due to compression of air) which in turn causes detonation earlier. You can deal with this with better cooling or, if you can't cool it enough, you throw in more fuel to help prevent detonation. (I realise you know this, I just have to say things in order otherwise I forget stuff).

 

Most car companies (and as a result tuners) will use a higher AFR for charged cars to help keep temps down for a longer period of time because other methods of cooling are too expensive or impractical.

 

But, if you are doing time attack and looking for max power just for a lap or two and so don't care if you only have peak power for a short period, you could run a map that runs optimum AFR (power/torque) until your IAT reaches the point where detonation may become an issue and then pumps more fuel in (which will obviously dial back power but save your engine from cooking itself).

 

Just a thought.... Not saying you should do it and note if your TMAP (or whatever is reading your intake temps) ever fails it may cook your head/melt your valves.

 

And I am now bowing out..... If you want any more than the above then someone with more knowledge than I have needs to step in here as I am just repeating stuff I heard. Sources were reliable so I have no doubt it's right, but I'm not an engineer so if you want to explore running a leaner AFR for more power for a short period of time then you need to check with someone who isn't me...

 

 

[turbotoaster]

the actual power loss from running slightly richer isn't really in the scheme worrying about, if your in a spec series running learner may give a small increase in power and carrying less fuel is always a bonus but since im not racing identical vehicles I feel its negligible, for example at 6500rpm I added fuel to move the afr from 12.6 to 11.7 and lost 3bhp so I can live with that.

 

The only thing im not monitoring at the moment is oil temps,(I do run an oil cooler) but im happy with water and inlet temps so my current opinion is the only thing that will let the car down now is mechanical stress failure, either rods, pistons or liners.

 

I also already have it add more fuel from when it exceeds 50c which is also a useful feature to let me know if the temps are rising as if I look over at my AFR gauge and im reading rich which I have an idea that something isn't right temp wise.

 

Until I get it on track again I wont 100% if I have everything covered but I think the car is pretty much done now until I build the forged lump in the future, so im hoping with practice and setup time I can turn some respectable laps

[turbotoaster]

little update, good news, the intercooler has helped with power output, at 19psi we are now up to 317bhp and 320ftlbs of torque, bad news is the clutch cant take it so now need to turn it down until i can put a better clutch in it.

 

Ive had it up to 22psi on the road in which it must be circa 340bhp and it is starting to feel a nippy now, i think with a better clutch, bigger injectors(22psi is 95% on 470cc at 4bar pressure so around 570cc) and a 3 bar map sensor and i think with 22-23psi will be perfect as long as it is doesnt break.

 

Just trying to get a day off work for a track day the moment

 

https://video-lhr3-1...843&oe=55D60E8B

 

little flame at the end

Edited by turbotoaster, 20 August 2015 - 03:46 PM.

[chris_uk]

That pax window has a bit of wobble lol.

[turbotoaster]

yep, i have latches that hold them in which you fasten up when your inside but since i needed to open the passenger door to speak to the dyno operator i didnt see the point in closing them, he said the engine sounded pretty happy and smooth on the dyno so my pikey mapping must not be to bad

[CocoPops]

What's the latest on your build Lee? It's been a month without updates?

[VX Mark]

I saw a post from turbotoadster on SELOC earlier asking about stripping down to the tub. I hope all is well. 

[CocoPops]

Uh oh

[Kieran McC]

On Face book it flew on fire😯