it is when you have a built engine with 10:1 compression. English's setup is friggen' awesome.

 

Lucas always seems to make a ton of power with few mods and/or small turbos. He's been of that mindset since long before the EVO came out, the IX turbo seems to have just been the next logical step

Tom

 

You need some more boost there bro.

 

It’s as easy as compression, and overlap with a small turbo. The higher compression of Lucas’s engine needs the extra duration and lift on the exhaust to get the pressure out after the combustion stroke..

 

Yea, she should get down on E85

 

^for sho!

 

Yes, yes, and yes.

JB from Lucas' account.

 

A more radical cam will decrease turbo efficiency more rapidly, assuming of course that the engine responds to it, not the other way around. The more efficient the engine at high rpm (the more power it makes), the harder it will be for the turbo to maintain pressure, all else being equal of course. If there is a restriction somewhere, the turbo can maintain high boost and efficiency all day long, because the engine is down on airflow.

Increasing airflow makes the turbo effectively smaller.



Actually Greg, the reason why longer duration cams are relatively forgiving of higher compression at moderate rpm is because some of that mechanical cylinder pressure is lost through the exhaust valve during overlap at lower rpm. This effectively reduces the dynamic compression (the only compression that really matters) at low rpm. When rpm rises and less static cylinder pressure escapes, this is where a high compression ratio will test the limits of fuel octane.

WRC cars use a small turbo with BIG cams and can run 40 psi with 10:1 SCR and 98 RON. They can do this because the BIG cams bleed off some of that compression at low rpm, and by the time this effect tapers, the turbo is losing efficiency (dropping boost). They don't spin those motors faster than about 6500rpm.

Big cams, higher compression and small turbo is forgiving to fuel octane. The bigger the turbo however (the more efficient at high rpm), the bigger the problem fuel octane will become.

 

Like Ted B said it makes it even more unlikely.

There is no way you are holding 28psi on the stock turbo. Not going to happen, ever. It won't even happen on a FPgreen which is more efficient, but you might get close. I have seen about 25psi at 7600 on a green.

If you are indeed logging 28psi at fuel cut off then I would look into the calibration of the MAP sensor.

 

I try to be careful about using "can't" and "won't", but we can say that being able to hold more boost implies the engine is mechanically using less air (lesser power potential), that's all.

 

Ahhh ok I guess I'm liar then, just for you I will get up with jhanksevo do a log and video record his defi boost gauge since its so hard to take my word. I have logs with me holding 25psi on my stock turbo @ 7500.

Thanks for the info Ted B., it always makes so much sense when you explain things

 

Defi gauges are known to be off. I've seen some off by 2psi on the high side.

Now you are saying 25psi. Before you where saying 28psi.

I am not calling you a liar. Far from it. Just trying to say that there is possibly an error in what you are using to monitor boost, and now that you mention you are using a Defi gauge, I now understand.

Most boost gauges and human eyes are deceiving and are not an accurate way of measuring boost across the rev range. Actually logging with a high quality properly calibrated MAP sensor is.

I personally have three ways of measuring/showing boost in my evo, and when I am on the dyno, I have four. All four do not agree with each other, but I do always reference my high quality properly calibrated MAP sensor as the bench mark overall.

 

Logs of 2 Byte Airflow would be interesting to see for people claiming the stock turbo holding anything more than 22psi after redline.

My pump gas Green tune pushes 2240Hz @ 7000RPM, approx. 45lb/min. This is 26psi, 275% load, and 81% WGDC on the stock solenoid with #65 pill and Forge WGA.

 

Just a note, I would also be careful of comparing 2byte airflow between cars as well, as well as comparing power from 2byte airflow. It can be skewed by different mods that can tweak MAF readings and airflow.

As an example, I had two evo 9's on our dyno, both with FPgreen turbos. One was using 104 octane and made 370whp. One was on 91 octane and made 335whp.

The 370whp Evo 9 was logging less total 2byte airflow, and of course less lbs/min then the 335whp Evo 9. Both had different intakes. One had a straight bolt on filter to the MAF with the OEM induction tube, and the other was using the HKS "mushroom" filter with a HKS metal induction pipe.

However, what you can do is measure differences in 2byte airflow on the same Evo back to back with more boost and less boost. This would be more of an accurate data sample on if you are getting more airflow or not from more boost or you have reached the point of no gains from holding more boost. You can also do this, to a point, with IDC changes as most of the time more airflow means more fuel needed. You would need a very consistent fuel tune for this however.

 

While tuning his car I was using a jdm map sensor & his defi gauge since he can play it back but mostly using the jdm map sensor. I said I can hold 25psi @ 7600, not jhanksevo. The 28psi hold was on jhanksevo car. I trust the sensor more than the gauge but the gauge like you mention did read higher. The logs say 28.xxx @7900. I know its hard to come by, I was even shocked myself & yes I do log 2byte load, rpm, airflow. Now are you going to tell me that I cant hold over 300 2btye load on stock IX turbo to 5500?