I agree with Mark, 100 octane is a must over 1.2 bar, you will start bending rods due to torque power.

 

sounds awesome...but i think you are running too much boost for pump....

 

Ok, this is killing me. Majority vote says it's too much boost, but the experts (IA and GIAC) say it's fine. But I'm gambling my motor...

I realize the boost spike is a result of the smaller exhaust side on the turbo creating boost so quick. How should I control it? Aftermarket boost controller, external wastegates, can a tweak on the tune take care of it?

I also realize that boost pressure (bar) and volume (cfm) are NOT the same thing (ex: 1 bar in a garden hose is less airflow than 1 bar through a 3" pipe, but both have the same pressure). I have opened up my entire intake path so my 1.3 bar is likely pushing a lot more air than a stock intake system. But since the motor internals is stock, does this matter? I mean can the motor make use of this extra airflow and if so does that mean my motor is under even more stress?

Colby

 

if my grandmother had ***** she would be my grandfather....boost is boost.I am not questioning the experts.....but I would never run that much on stock internals and making it even worse your on pump.Most whom have already been on the path your currently on are telling you its too much boost.Honestly do a search and see how long the seasoned members have been singing the same ol song.You are pushing allot more CFM with your setup VS a K16 car, and ask yourself how many guys are running 1.3 bar with the smaller turbo with allot less CFM.What are you AFR's?

 

If you want to know that answer simply get it in writing... from both tuner and installer... I bet none will sign that paper and thus there is your answer...
last time somone one was running 1.5 bars on pump on a Evoms gt700( DMK) he blew it up... food for thought..
markski

 

Mark,you are wrong,the car did not "blow up "because of that the car had 109 in it from the night before(he filled up at Evo).......he missed a shift by 2 gears ....end of story .....I saw the type 2 overrevs pulled out of the computer the next day...... 6500rpm over will blow any motor.And no tuner is gonna sign a paper like that not IA,Evo or Proto.He was never instructed he could run 1.5 bar on pump by Evoms......Were you there?
More people have blown up their car by running a boost controller on a bolt on kit(where there shouldn't be one) than anything else.IMO a boost controller on a 600-700kit is a recipe for disaster because the factory protection is gone and the end user's temptation to crank it is too great.Only a few have the self control to use one and the others that don't lack the protection to keep their motors safe.I do agree that 1.5 bar on pump is too much boost.

 

Joe,
I was not picking on evoms but mearly trying to get it thru some hard heads that running 1.6 bars on pump is not safe... on gt28s....
However, as far as your explanation of the cause.... I don't disagree... sure I was not there... but Don did tell me privately that he ran pump gas... and was running 1.5 bars at +150 mph.. so I took his word for it.
could the Type 2s been from previous runs? was it time stammped...
Either way...
would you run your car on Evoms , proto, etc... whatever tuner car with gt28s at 1.6 bars on pump gas knowing what you know now? I really doubt it.
I have much respect for parties involved... so no hate stuff here... I personally would never do it now knowing what know...
mark

edit: I agree that the Greddy is not for everyone....

 

It feels like your Grandmother is your Grandfather..
Boost ain´t relevant in the big picture.
The relevant part is
How much air is going into the engine(the water hose principle is correct), what temperature does the in going air have, do you have enough fuel. How much backpressure do you have from the turbos(also temprature driven).

When those parameters are ok then you have to look att how much power the engine is producing in the different RPM:s.. I´ts not that common that you bend the rods on brute force due to high HP(Not impossible do ;-).. Its much more common that your engine falls apart due to knocking or/and high RPM wich makes the pistons crack or the stock rods to give up due to fatique.

I personally will go with profec BC. But In my opinion the safest way is to stay with stock Oem BC, because if the tuning is correct done the ECU has alot of possibilities to save the engine with adjusting the timing and lowering the boost! With aftermarket BC you take away that opportunity!

Regards
Pete

 

I have not read the whole thread, but if the OP is getting boost numbers from the stock gauge, might they be inaccurate?

I believe my gauge consistently reports 0.1 bar higher than the program is supposed to allow. Others with more than one gauge can probably answer this more authoritatively.

 

I am surprised no tuners are commenting....

My 2 cents.

I suspect that uncoupling the BC from all the other control parameters available to the ECU severely limits the boost control. The time it takes a boost controller to respond, and change pressure and open a waste gate is AGES compared to the microseconds to pull timing or enrich the mixture.

I also know that relying on simply the mechanical response of the wastegate to open "at 1.0 bar" following a transient boost spike to 1.8psi could be problematic. Again, this mechanical motion is a long time compared to an engine revolution.

These should not be overlooked when adding an external BC. I would want alot more clarification from my tuner on how they are protecting the motor under these conditions.

A

 

As I posted earlier 1.6 is a bit higher than we normally see, and I would prefer to see it a bit lower. As long as the DME has full control of the turbos that file should run 1.4 to 1.5 bar in the lower RPM range and then drop to the 1.3 - 1.4 range after 5500. The wastegates may be set too tight, give us a call and we can help you figure it out. 949-724-0014.

You are correct that pressure before the throttle body is not the whole picture. Rods bend when cylinder pressures, or torque and power, are too high. Race gas normally does not have a direct affect on cylinder pressures, except to alleviate knock, which can increase cylinder pressure. If ignition happens well before top dead center, like in the case of knock, cylinder pressures can spike. -4 degrees of correction is the most knock activity we saw on your file, and this was on a car with stock intercoolers and 70 C intake temperatures.

With that said increasing the power output from your motor can increase strain on connecting rods and adding a couple of hundred plus horsepower and foot-lbs of torque could lead to a bent rod at some point in the motors lifetime. A good conservative path is to upgrade rods, however at 1.2 bar an aggressively tuned K24 car may be as fast.

There may be some discrepancy between different customers on what boost they see and it will depend on where they are reading it from.

- The dash is not always accurate.
- There is usually a pound or two of pressure drop between the Y-pipe and the intake manifolds so a boost gauge reading pressure from a manifold vacuum line will read lower.
- If a shop adds a diode to the pressure signal, the dash and a scan tool will both read lower than actual boost.

 

Hi Andrew-

What does "full control of the turbos" mean? No external boost controller?

Thx

Adam

 

right I wouldn't,hell i won't even run that on my built motor,yeah it would probably last for a while and make even more power but not worth the risk.

 

1.2 max for me w/ GT28s Proto 650

 

When I had my gt700 kit it would make 1.5bar on pump and race. There is no way to control the boost with this kit. If the vendor wants to sell a kit this way they better back it up 100% when a motor blows!