I bought a Turbotech manual boost controller and I'm confused!

[Sydo]

I fitted one of these last week myself.
I initially noticed a huge difference all round!

I do a lot of open road driving however, and would continually get boost cut around 4000rpm in 4th while overtaking (yes, this equals about 120kph). Now I've had to wind the valve back so far to overcome this issue I am no longer sure if it has any positive affect over the stock standard setup..

 

[naughtika]

seems similar to what i was getting.. have you replaced your plugs?

 

[BuzzPuppy]

Did you end up solving your problem with the boost cut Christian?

 

[naughtika]

nope.. i still occasionally get it.. and oh yah.. i haven't taken off my boost controller haha.. i'll do that tom..

also what i've noticed is.. it happens when i've pressed the accelerator at around 75%, 3rd or 4th gear revs is around 3500rpm going up.. but if i press the accelerator with a nice smooth incline.. it doesn't happen..

 

[Sydo]

seems similar to what i was getting.. have you replaced your plugs?

No, but I don't think this is the problem.

also what i've noticed is.. it happens when i've pressed the accelerator at around 75%, 3rd or 4th gear revs is around 3500rpm going up.. but if i press the accelerator with a nice smooth incline.. it doesn't happen..

I'm going to do some testing during the week, comparing stock to controlled boost. I'll keep what you've said in mind. I do suppose that smooth acceleration is probably going to cut back any issues with boost spiking.

I guess this is a issue that not a lot of members here would have experieced. 95% of my daily driving is done over 80kmph - so boost cut in 4th gear is quite a big problem for me.

 

[SLY-031]

nope.. i still occasionally get it.. and oh yah.. i haven't taken off my boost controller haha.. i'll do that tom..

also what i've noticed is.. it happens when i've pressed the accelerator at around 75%, 3rd or 4th gear revs is around 3500rpm going up.. but if i press the accelerator with a nice smooth incline.. it doesn't happen..

Definately boost cut and not a fuel supply issue?

 

[Murph]

it does and you only need to disable it when going full EBC,
not when installing a bleed valve like this.

Any chance you can give me some more details on the stock boost control setup? How does it work, what components does it use and under what conditions does it operate?

the best thing about these is that they work off pressure rather than just bleed. They work in a similar way to a solenoid and which makes it far harder to spike, there is just no reason to get a bleed valve when these are so cheap better response than a bleed as well. In my case it held boost better than the stock wastegate. As far as im concerned this is the best $30 mod you can add to your arsenal.

They all work by bleeding air off the wastegate line. The turbotech is just a gated bleed valve, nothing special about it. The turbosmarts do the same thing. There's some dodgy sh*t in the "explanations" of how it work on that ebay link.

The solenoids used with an EBC aren't really any different in how they work either, they're just bleeding air off. The difference being that they're actively controlled.

No, but I don't think this is the problem.

On several occasions I've experienced what seemed to be a boost cut, but was just the spark getting blown out due to a combination of plug gap being too wide and too much boost. Basically, as you increase boost pressures you also need a stronger spark to ignite the fuel air mixture. You can do this by either using more powerful coil packs, or gapping down your plugs so they don't have to arc as far.

It can feel pretty much like a boost cut, total loss of power, not just like a stuttering miss fire. If you're still running lowish boost, then it can't be the boost cut.

"Boost cuts" are usually either based on reaching a certain inlet pressure, or what is actually an airflow cut, based on exceeding the maximum voltage of your air flow meter (eg. all the nissans). Not certain which these cars do. Eitherway.....for a stockish example you shouldn't be seeing it below ~14psi.

Now if it had an airflow cut and you had a big FMIC, exhaust and some big turbos, you'd be getting a lot more air in for a given boost pressure, hence would hit the cut somewhere closer to 10psi. I've seen exactly that situation before on a mates 180sx.

 

[Sydo]

On several occasions I've experienced what seemed to be a boost cut, but was just the spark getting blown out due to a combination of plug gap being too wide and too much boost. Basically, as you increase boost pressures you also need a stronger spark to ignite the fuel air mixture. You can do this by either using more powerful coil packs, or gapping down your plugs so they don't have to arc as far.

It can feel pretty much like a boost cut, total loss of power, not just like a stuttering miss fire. If you're still running lowish boost, then it can't be the boost cut.

"Boost cuts" are usually either based on reaching a certain inlet pressure, or what is actually an airflow cut, based on exceeding the maximum voltage of your air flow meter (eg. all the nissans). Not certain which these cars do. Eitherway.....for a stockish example you shouldn't be seeing it below ~14psi.

Now if it had an airflow cut and you had a big FMIC, exhaust and some big turbos, you'd be getting a lot more air in for a given boost pressure, hence would hit the cut somewhere closer to 10psi. I've seen exactly that situation before on a mates 180sx.

Very interesting! Thanks for the info.
I'll have to look into it over the weekend.

 

[Murph]

Very interesting! Thanks for the info.
I'll have to look into it over the weekend.

Not a problem.

If I recall correctly, standard plug gap is 1.1mm. Try getting some gapped for 0.8mm. That usually works a charm with all the nissan motors I've worked on.

 

[Guest]

I AM SOOOOOOOOOO DOIN IT. thaks guys....
12 psi or may be 15.... wooohoooo

 

[Guest]

0.8 gap will be necessary when we boost it up high, on my s14 we run 1.5 bar sometime on time attack track day i go for 1.6 -1.7 bar but definately 0.8 mm gap wil help otherwise the car will flutter etc.

 

[BuzzPuppy]

Just bought one of these TurboTech MBCs moments ago to see how it all works.

Now that I'm back from Nepal/Mt Everest Base Camp, I can spend on mods/maintenance! Still on the shopping list are spark plugs gapped to 0.8mm and boost guage.

Gauge in first to gather a baseline as well as logging basic data through my lil' Apexi RSM (where the clock used to be ).

See how we go?

 

[naughtika]

Gavin, I recommed to install the gauge first.. then do your plugs.. then the MBC, therefore you get to feel when you boost your car..

 

[BuzzPuppy]

Yep, planning to do it in that order Christian

Kind of like monitoring brand new servers...

1) Figure out what you have
2) Perform tests to establish baselines... ie: what is normal.
3) Introduce one change at a time, measure effect and evaluate
4) Fine tune

So I'm going to apply my approach to Loki. Problem is, if I screw it up, it's not like I can reformat and start over. Engines die. Front cut time!

 

[Hotwire]

I'd install the boost gauge first!! The last thing you want to do is over-boost harming turbo's or worse the engine (leaning it out)
... best to know what level it's starting at, then modify boost levels.
If you increase boost too much you're asking for trouble.

 

[snickells]

Gav, let me know if you want a hand installing your gauge/MBC.

 

[BuzzPuppy]

Yes please!