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It is a 14psi actuator with the preload it has on it the turbo spikes to about 20 then tapers down to 17psi. Am using an MBC also.

Tuner was Hi-power racing in Slacks creek they are more Honda guys but the tuner they have there Ben does a lot of nistuning stuff

An unfortunate reality that I have experienced a couple of times is being knock limited by day-of-tune boost control.

Through the collection of experience and notes from various tuners I have come to realise that unless the tuner has a prior base map to go off (from a car tuned per my next instructions) that a tune will generally turn out rat shit. So if you rock up to a tuner with an SR20 and a T28, they will load one of their many thousands of T28 tunes and tweak it to suit your specific car.

However, when a tuner doesn't have this I generally find that they will start at minimal timing and try advancing one degree at a time until the car reaches its peak. I have specifically found that this leads to seeing detonation fairly early and the power 'plateauing' before it ordinarily would. Usually being 20 or 30kw off 'optimal' but often with the tune looking otherwise 'OK'.

What I suspect is the case is that a given motor combination will have what I call a 'knock valley' before optimal performance is achieved. That being that it will knock easier at a given timing and AFR value than it would had it been elsewhere on the load table, namely somewhere at a more aggressive tune state.

What I believe to be the correct method of tuning, and way of avoiding this issue, is to start with as LITTLE boost as possible. That being under 10psi. Then tuning at this level for the most aggressive tune possible. Once achieved the tuner should then increase boost by small increments and dial back the tune in the newly reached load cells as necessary. The idea here is that the tune will pass the 'knock valley' and you will end up with a far more aggressive tune once you reach target PR.

Thus giving your tuner the car with a minimum boost of 20psi up top will result in you having a dull top end.

People should familiarise themselves with this issue when building their cars, and not expect the tuner to be an all out god in this respect. You should make sure that your car can run a flat boost level of sub 10psi before you pay the tuner to go balls to the wall and you should specifically ask them to tune in this way.

Stao, moving forward you should not only trial your turbos at holding 20psi flat but also being perfectly controllable sub 10psi. Ideally you should supply the turbo with a 8 or 10psi actuator and a given end user should be able to use a typical boost controller to turn it up to target pressure WITHOUT need of changing actuators. This should be your goal moving forward, as it will help customers achieve better results more regularly.

I hope this helps.

You mean to say that tuning per my described 'optimal' method would require the base tune to be really good?

If so I find that odd because my described method is meant to be a noobs guide to a good tune starting from scratch.

But I believe you are referring to the 'use a base tune' method which I am saying most tuners do but am strongly advising against. In which case I agree the base tune would need to be GREAT and generally occurs where a tuner isn't really good. Unfortunately my car was tuned under such conditions, and minimum boost was 18psi. Says a lot.

However I don't believe your post reflects the later, am confused and would like to know where you stand (plus it will help others know what an experienced tuner thinks of the above). Your opinion IS HIGHLY valued on this forum, don't disregard that fact.

it's harder to control boost with an actuator that's got a lower rating, and yes your method of tuning is good.. but tuners have a business to run and you'll find that 9 out of 10 cars will have nearly the same ignition map (provided they are the same car with same same but different turbos).

Most tuners just tidy up the AFRs then do a few power runs and go here's your dyno print out, and I've "supposedly" spent XYZ hours doing your cold start tune, hot sauce tune, whatever the fk they ramble about.. because cold start isn't really a tune, it's just setting up your cold start table & idle valve duty cycle.. usually can be left as per the base map and works.

Ok, I should stop rambling before I offend people.

But I believe you are referring to the 'use a base tune' method which I am saying most tuners do but am strongly advising against. In which case I agree the base tune would need to be GREAT and generally occurs where a tuner isn't really good. Unfortunately my car was tuned under such conditions, and minimum boost was 18psi. Says a lot.

Blargh sorry I was a bit too hasty in my writing and didn't give myself time to give sensible wording - sorry, not your fault it doesn't make sense haha. What I was essentially thinking about when I blurted out that discombobulated stuff - which was half

me being bewildered that it is apparently that common for bad results to come if the base isn't good, was that the previous tune should not matter one iota if the current tuner is actually a competent tuner... from what you posted there, there must be a lot of shit tuners out there!

When I tune, I adjust things to make everything run the way they should - whether it is a supposed base map/previously tuned car or if I think I am starting from scratch. You have to check EVERYTHING to make sure it's where it should be, and of course I've made (fortunately more trivial than breaking a motor or anything really nasty) boo-boos to learn exactly how much that really matters... basically tuning from a base map might make things slightly easier if the map is close to right for a lot of stuff, it isn't then I'd just anticipate a good tuner to just take longer to tune as more things will clearly be not quite right and need adjusting.

But yeah, gotta remind myself to just read and shut up - especially if I don't really have enough time to post in proper English - sorry!

LOL all good.

Per John's post a vast majority of tuners here keep a database of prior tuners, and when you rock up they will ask for injector and turbo size. You will specifically be asked what size your turbo is similar to if it is unheard of.

A prior tune will be loaded, it will be tidied to reasonable parameters and will be onto power runs. Tunes take under an hour on cars that don't present issues. Fact.

LOL all good.

Per John's post a vast majority of tuners here keep a database of prior tuners, and when you rock up they will ask for injector and turbo size. You will specifically be asked what size your turbo is similar to if it is unheard of.

A prior tune will be loaded, it will be tidied to reasonable parameters and will be onto power runs Tunes take under an hour on cars that don't present issues. Fact.

On the money here, then one loads up their car on the race track or a 1 mile race at an airport strip and blows their motor.

Often a naughty little trick to get mad numbers on a dyno is to shorten the ramp rate and run it in 3rd... then when a car actually truly gets loaded up kapow..

An unfortunate reality that I have experienced a couple of times is being knock limited by day-of-tune boost control.

Through the collection of experience and notes from various tuners I have come to realise that unless the tuner has a prior base map to go off (from a car tuned per my next instructions) that a tune will generally turn out rat shit. So if you rock up to a tuner with an SR20 and a T28, they will load one of their many thousands of T28 tunes and tweak it to suit your specific car.

However, when a tuner doesn't have this I generally find that they will start at minimal timing and try advancing one degree at a time until the car reaches its peak. I have specifically found that this leads to seeing detonation fairly early and the power 'plateauing' before it ordinarily would. Usually being 20 or 30kw off 'optimal' but often with the tune looking otherwise 'OK'.

What I suspect is the case is that a given motor combination will have what I call a 'knock valley' before optimal performance is achieved. That being that it will knock easier at a given timing and AFR value than it would had it been elsewhere on the load table, namely somewhere at a more aggressive tune state.

What I believe to be the correct method of tuning, and way of avoiding this issue, is to start with as LITTLE boost as possible. That being under 10psi. Then tuning at this level for the most aggressive tune possible. Once achieved the tuner should then increase boost by small increments and dial back the tune in the newly reached load cells as necessary. The idea here is that the tune will pass the 'knock valley' and you will end up with a far more aggressive tune once you reach target PR.

Thus giving your tuner the car with a minimum boost of 20psi up top will result in you having a dull top end.

People should familiarise themselves with this issue when building their cars, and not expect the tuner to be an all out rajab in this respect. You should make sure that your car can run a flat boost level of sub 10psi before you pay the tuner to go balls to the wall and you should specifically ask them to tune in this way.

Stao, moving forward you should not only trial your turbos at holding 20psi flat but also being perfectly controllable sub 10psi. Ideally you should supply the turbo with a 8 or 10psi actuator and a given end user should be able to use a typical boost controller to turn it up to target pressure WITHOUT need of changing actuators. This should be your goal moving forward, as it will help customers achieve better results more regularly.

I hope this helps.

This is how i had been taught aswell, set timing fairly aggressive with low boost and go up in small steps and adjusting ignition as you go.

I've also seen one "tune" which was nothing but a "mines" bin file copy pasted and 2 degrees trimmed from the entire map.

Edited by Super Drager

You will find most tuners DO NOT tune in that method.

Majority of them won't bother resolving boost creep issues and will just tune with them. And the majority of us have cars with boost creep.

It sucks because we are not to know if there is creep before we take it to the dyno, as we cant exactly boost an untuned car.

You will find most tuners DO NOT tune in that method.

Majority of them won't bother resolving boost creep issues and will just tune with them. And the majority of us have cars with boost creep.

It sucks because we are not to know if there is creep before we take it to the dyno, as we cant exactly boost an untuned car.

Being honest now a lot of tuners won't take any real time to tune a car properly unless it had been built with them or a very large sum of money has been spent with them.

I know one shop didn't even use knock detection equipment to tune unless you had spent a fair amount of money with them ;)

Totally agree. I won't name names but I have definitely seen my share of what you just described.

I will say though, DVS JEZ is totally honest in this respect and will do his best regardless of who built the car. He is by far the most honest tuner I have seen, so much so I'd be happy to work for him as a mechanic.

Did some evaluation and testing today based on the differences those Tomei 264 / 9mm cams. In which Tomei should have done before considering selling those to the market.

The Test turbo was a SS2 Alpha with VNT turbine.

My original result was:

powerall.jpg

boostall.jpg

Same turbo, Tomei 264 / 9 Cams:

power.jpg

boost.jpg\

Isn't this identical with your original SS2's result with abit more top end?

power.jpg

Edit:

After having a closer look those cams did increase mid ranger from 4000RPMs and on wards.

Edited by petero'nell

Umm, I'm trying to get my head around GTScotT's and Lithium's discussion above ... Can someone please summarise why running a high PSI actuator is not ideal? Thanks

because you're unable to load up certain cells in the map to correctly tune them, those cells are often linearised/interpolated and are guess values for ignition and injection

Summary of the above posts for the benefit of V28.

It is not ideal to START tuning with a high psi actuator. What you really want to do (especially if starting from scratch without a good comparable base tune from the same or another vehicle) is to start with a low boost level, tune that aggressively, then increase the boost in smallish steps, Aggressively tuning the new parts of the maps that you reach as you go. If you have to soften the tune in already tuned parts of the map because you're hitting them (earlier) with more boost, then do so to avoid it pinging.

As you go you'll run out of ability to get good boost control from a soft actuator being held up by a boost controller, so THEN it makes sense to switch to a higher pressure actuator.

Other part that became a limitation factor is with the boost tapering with internal wastegate setup. Which there isn't much could be done apart from having a very free flow induction (inc cooler) and exhaust system. So I will be doing very precise measurements in terms of wastegating, the boost level will be physically set through the turbine housing to hold a more specific range and nothing less.

Umm, I'm trying to get my head around GTScotT's and Lithium's discussion above ... Can someone please summarise why running a high PSI actuator is not ideal? Thanks

I don't think it matters If you will always be running fixed boost level. Ie. 18psi . because the Timing and fuel distribution table is running based on scale of RPM to PSI. So it will always be running on those cells of the timing / Fuel table.

How ever if different boost level is used then the data in reference to the active cell might not be accurate, starting from low moving to high is more of inputting cell data in those areas, for it to work accordingly regardless of what ever boost is used to the highest boost level.

So having said all those if the minimum boost level on the turbocharger is set to 16psi and maximum is 20psi then realistically it will only need the data responding to within those boost changes.

Yuck, if that is acceptable over there (seems to be pretty common) maybe I should head over there and hire my services, probably not hard to look amazing :-P

Sent from my GT-I9505 using Tapatalk

You won't make boost cruising at 100km/hr unless your putting your foot flat for some reason

I make boost cruising at 60 in 4th, you can hear it spool and feel the torque increase, by 2500 its making like 10psi

Then one day there's an issue with your waste gate, etc.. you hit those cells that have bogus interpolated/linearised numbers and POP... (well hopefully whoever has tuned it has plugged in safe numbers so it never happens, but it's possible).

I bet most of the cars out there tuned by shitty shops will have cells that have the base map ignition values.. on the dyno those values probably won't be loaded, till they decide to climb a hill in 5th then pop.

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