OP
OP
yeh something like that! nothing chromed like bodged on it now (two HUGE 3"ish center exits!) is yours pretty quiet to?
Tuning turbo time!
- Thread starter craigb244
- Start date
Currently reading:
Tuning turbo time!
- Joined
- Feb 16, 2005
- Messages
- 5,983
- Points
- 988
Set PWM current limit to 100% and PWM threshold to 25.4 if your injectors are high resistance.
Your timing is 4 degrees out from mine (maybe not an issue, they all seem a little different. Did you check with a timing light though)
Barometric correction is enabled. Maybe you can teach me about this one, as i know nothing about it lol
Is fuel cut rev safe on a turbo? Play with the CLT rev limiters though, its usefull to have a rev limit kick in a a high temp, say 110, then you can feel something is wrong if your not looking at the temp gauge
Overrun fuel cut has eaten a few o2 sensors of mine, they cool too much on long coast downs and shorten the life. I'd personally run stoich on overrun. WB lambdas aren't cheap.
Programming the LC1 and MS for a 10:20 afr gives a higher resolution. the extra few afr range on the default setup are of no tuning use anyway.
Your maximum saprk duration is VERY low. you should be looking at a 1-2ms figure here. don't confuse this with the MS1 min spark duration. Also your dwell can probably go up a fair bit for a stronger spark. Your coils will take at least 3ms before saturating.
Look at your tpsDOT values as you are using TPS based accel enrichments. You trigger acceleration only once in the entire log reduce the threshold and adjust the curve. If it feels ok though, you may not need any enrichments at all
I can see you have played with lag factors. Out of personal preference, i leave these at 100 (unfiltered). You may have a bit of a noisier signal, but its not delayed at all
AFR's on idle look a little rich.
Looking good so far though You can run much lower afr's than me before a missfire. I struggle to get 12.5 without missfiring. Probably due to my high compression.
Keep it up and have fun
Kristian
Your timing is 4 degrees out from mine (maybe not an issue, they all seem a little different. Did you check with a timing light though)
Barometric correction is enabled. Maybe you can teach me about this one, as i know nothing about it lol
Is fuel cut rev safe on a turbo? Play with the CLT rev limiters though, its usefull to have a rev limit kick in a a high temp, say 110, then you can feel something is wrong if your not looking at the temp gauge
Overrun fuel cut has eaten a few o2 sensors of mine, they cool too much on long coast downs and shorten the life. I'd personally run stoich on overrun. WB lambdas aren't cheap.
Programming the LC1 and MS for a 10:20 afr gives a higher resolution. the extra few afr range on the default setup are of no tuning use anyway.
Your maximum saprk duration is VERY low. you should be looking at a 1-2ms figure here. don't confuse this with the MS1 min spark duration. Also your dwell can probably go up a fair bit for a stronger spark. Your coils will take at least 3ms before saturating.
Look at your tpsDOT values as you are using TPS based accel enrichments. You trigger acceleration only once in the entire log
reduce the threshold and adjust the curve. If it feels ok though, you may not need any enrichments at all I can see you have played with lag factors. Out of personal preference, i leave these at 100 (unfiltered). You may have a bit of a noisier signal, but its not delayed at all
AFR's on idle look a little rich.
Looking good so far though
You can run much lower afr's than me before a missfire. I struggle to get 12.5 without missfiring. Probably due to my high compression.Keep it up and have fun
Kristian
OP
OP
Set PWM current limit to 100% and PWM threshold to 25.4 if your injectors are high resistance.
never noticed this! would of run like this since i fitted megasquirt.
DONE
Your timing is 4 degrees out from mine (maybe not an issue, they all seem a little different. Did you check with a timing light though)
used timing light when i installed the ecu. i guess 4degrees is within manufacture tolerance?
Barometric correction is enabled. Maybe you can teach me about this one, as i know nothing about it lol
not sure about this! cant remember setting it. but it works so ill leave it. initial map reading? i thought thats was ms(and all) ecus do anyway.
Is fuel cut rev safe on a turbo? Play with the CLT rev limiters though, its usefull to have a rev limit kick in a a high temp, say 110, then you can feel something is wrong if your not looking at the temp gauge
Overrun fuel cut has eaten a few o2 sensors of mine, they cool too much on long coast downs and shorten the life. I'd personally run stoich on overrun. WB lambdas aren't cheap.
ive read into this. it is safe on turbos. never had a problem with my lambda going over cool maybe its down the the exhaust? ill be removing the WB as soon as its all tuned anyway and fitting a NB just for idle. good idea with the coolent thing
Programming the LC1 and MS for a 10:20 afr gives a higher resolution. the extra few afr range on the default setup are of no tuning use anyway.
how do you do this?
Your maximum saprk duration is VERY low. you should be looking at a 1-2ms figure here. don't confuse this with the MS1 min spark duration. Also your dwell can probably go up a fair bit for a stronger spark. Your coils will take at least 3ms before saturating.
set that not long ago after a STRANGE failure of a coil pack or driver both randomly died. not sure what caused it and 7.5amp fuse never blew :bang:DONE
Look at your tpsDOT values as you are using TPS based accel enrichments. You trigger acceleration only once in the entire log
forgot about these! played with them once and could never feel anything so just left them... what are yours like?Set to megasquirt defaults which they say is a good starting point
I can see you have played with lag factors. Out of personal preference, i leave these at 100 (unfiltered). You may have a bit of a noisier signal, but its not delayed at all
Cant say ive messed with these. will set them to 100 and see how it goes DONE
AFR's on idle look a little rich.
that would be because when i swapped to the larger injectors i did a silly thing of leaving the fuel regulator hose disconnected. tuned it with an air leak so when i reconnected it the low (idle) went rich
Looking good so far though
Keep it up and have fun
Kristian
Last edited:
Just a little question, what size is the boost pipework. is it 2"??
OP
OP
yep!.
having mine replaced with stainless at the same time i get the exhaust done :slayer:
Kristian: thanks for the tip on the 10:20AFR thing. its WAY better. the reading at idle dont sway about half as much now
OP
OP
but alloy also conducts heat VERY well. i think the amount flowing thru these pipe makes any kind of heat soak a negotiable amount
The boost pipework doesn't need to be bigger than the smallest restriction in the intake tract , (intercooler input/output, Bob, TB etc) otherwise you can just end up building in lag
and back to my point that the TB doesnt need to be any bigger than the smallest restriction elsewhere, ie the compressor outlet?
OP
OP
nah-ah.
it's just going to help the turbo spool up quicker as it has less restriction on its outlet, it has less restriction because there is more space to fill before it hits a restriction (inlet valve).
yeah you'll get more lag, so when the turbo does kick in, it might feel like more power because it's come in at a different point.
edit; tom - sure i've asked this, what diameter is that stuff? and can it be mandle bent like stainless?
it's just going to help the turbo spool up quicker as it has less restriction on its outlet, it has less restriction because there is more space to fill before it hits a restriction (inlet valve).
yeah you'll get more lag, so when the turbo does kick in, it might feel like more power because it's come in at a different point.
edit; tom - sure i've asked this, what diameter is that stuff? and can it be mandle bent like stainless?
I have 50mm and 60mm. Dont know if it can be bent, ive yet to find out
On the bending, OJZ say they're willing to try. Obviously, you can't simply ask "can you bend Ti tube?" cos we dunno what grade Tom's supply is. It is tough stuff, though.
Personally, I've yet to come to a conclusion as to what would be better, but aluminium is certainly the most used.
As to the size, there's always a trade off between lag and driveability in turbo applications (which is why Lancia did that wonderful supercharger/turbocharger thing, or BMW are now doing small and big turbos in the diesels), but I'd have thought Martin's car really needs more lag rather than boost/torque spike........
Arc's idea is a wonderful peice of whimsy already -- or so it would seem -- blown to buggery by everyone who fitted trickers on high boost tubs and gained -- what -- 5 - 10 bhp over the VAD set up. My own view is that throttle size is largely going to be determined by the power output of the lump (be it NA or charged), that for a given area plenum set ups are more effective than ITBs on charged applications given MPI (the maths alone show that the butterfly shaft restriction on WFO is way bigger with ITBs).
Shame that without a dyno and lots of time and money we can't really confirm any of this for sure...............
Personally, I've yet to come to a conclusion as to what would be better, but aluminium is certainly the most used.
As to the size, there's always a trade off between lag and driveability in turbo applications (which is why Lancia did that wonderful supercharger/turbocharger thing, or BMW are now doing small and big turbos in the diesels), but I'd have thought Martin's car really needs more lag rather than boost/torque spike........
Arc's idea is a wonderful peice of whimsy already -- or so it would seem -- blown to buggery by everyone who fitted trickers on high boost tubs and gained -- what -- 5 - 10 bhp over the VAD set up. My own view is that throttle size is largely going to be determined by the power output of the lump (be it NA or charged), that for a given area plenum set ups are more effective than ITBs on charged applications given MPI (the maths alone show that the butterfly shaft restriction on WFO is way bigger with ITBs).
Shame that without a dyno and lots of time and money we can't really confirm any of this for sure...............
back to back torque curves for this? i want to see how it effects the useuable torque, not just peak power. if it's gaining more peak by just shifting the same amount of torque along the RPM range.. then
and i want to know WHY, why does opening the inlet tract 30mm before the plenum opens up anyway has an effect.
OP
OP
i had to do loads of research on metals for college... thats why I say stainless is better.
stainless is a pretty poor conductor. while aluminium is a VERY good one (they dont make kitchen pots and pans, computer heat sinks, cylinder heads/radiators out of it for no reason)
Not sure on the Titanium. guess it will greatly depend on the type. if it is cheap then i guess it will only contain a small amount of titanium and bend pretty easy. but even then there are alloys that are VERY stiff. so unless you know the type you cant other then trying.
Last edited:
Basically ITBs have the same set of compromises attached to them with a forced induction or N/A setup, you sacrifice mid-range for gains at the top end if done properly. As mostly forced induction engines are more about mid-range than top end the perception is that ITBs are bad for performance.
That said, if you make an ITB inlet track that would make a very peaky torque curve in an N/A setup the fact forced induction setups naturally make good mid-range fills in the lower segment of the rev range delivering a very flat torque curve.
Arc, the throttle body on a single TB setup is typically the last big restriction in the inlet track before the runners/inlet ports, this means it's having the biggest effect on the way air flows into & out of the plenum chamber. Also for minimum restriction of airflow you'll want a TB to be larger than the boost pipe. Yes a larger TB will push the torque further up the rev range but it'll also let you make more torque as an absolute figure at that higher rpm.
That said, if you make an ITB inlet track that would make a very peaky torque curve in an N/A setup the fact forced induction setups naturally make good mid-range fills in the lower segment of the rev range delivering a very flat torque curve.
Arc, the throttle body on a single TB setup is typically the last big restriction in the inlet track before the runners/inlet ports, this means it's having the biggest effect on the way air flows into & out of the plenum chamber. Also for minimum restriction of airflow you'll want a TB to be larger than the boost pipe. Yes a larger TB will push the torque further up the rev range but it'll also let you make more torque as an absolute figure at that higher rpm.
back to back torque curves for this? i want to see how it effects the useuable torque, not just peak power. if it's gaining more peak by just shifting the same amount of torque along the RPM range.. then
They are out there -- compare -- say, a VAD graph with one of the EVO cars.
But -- and Martin's car may be (as the most developed EVO car out there) a good example of why it can be better to move the torque peak along, maybe flatten it out. Point is that we don't tend to like revy NA cars with nowt at the bottom end (unless we have a very light shell to pop the engine in -- bikes, Elise/Elige, etc.) as they're hard to drive. BUT, you can have too much torque, too suddenly, too low down. This is what can make turbos a difficult proposition. A car which has a sudden torque spike can be very hard to get off the line, hard on clutches and driveshafts, spin wheels, etc.
This is one reason why I'm looking for a bigger turbo for Blue........
It'll be different NA and forced. On forced, I think it's just a restriction, and any restriction before the inlet valve has to be a bad, bad, thing. You can see it with poorly designed intercoolers, for example, and over-large ones (which are restrictive by accident, almost). On NA it's way, way more complicated.
