Once the car gets back from Texas we're doing some more testing on the intake side. Now we have all of our datalogging working and we have a pressure tap about 6" in front of the turbo inlet (one side). With stock airbox, air filter, and our intake pipes (stock intake plenum after MAF), I was seeing up to 3.5psi of vacuum at 600whp! Our pipes made a big improvement so I can't imagine what it was before. Removing the airbox gained about .5psi and 10whp, removing the stock air filter and running it open made negligible difference.

We got a nice carbon intake box from Vivid Racing with the dual openings and that picked up the 0.5 psi of pressure drop in the intakes. So now we're hovering just under 3psi of pressure drop. My guess is that replacing that intake pipe/plenum just after the MAF will make a significant difference and thats the next thing we're doing once we get back from Texas. I was really hoping to get it done before hand but we just ran out of time.

Just a quick update but I'll post more about our car including some graphs from the datalogs later.

-Martin

 

I'm not sure this is a good way to look at it. If you see vac on the intake side of the turbo it effects spool up and boost much more than what you measure. What I'm saying is that .2BAR of vac may effect the turbo performance much more than .2BAR of pressure. Spool will be slower, boost will be lower, the general efficiency of the turbo will just be off all around. Supercharged cars are probably the most tested\documented example of this and while it's not quite a direct comparison the amounts of power those kinds of cars pickup from simple mods on the intake side should certainly demonstrate just how important this can be for us. The closer to zero drop you get the more performance you get and really it's "free" with no downsides!

IMO this is a very important area to focus on even with stock turbo equipped cars!

P.S. AMS - which side did you tap? If you're following the OEM piping style the passenger side is much longer and probably the worst of the two! Would be interesting to know how big the differences are actually. <shrug>

 

Martin,

You need to measure the pressure just after the maf AND just before the turbos

That way you can measure the pressure differential between these two points

Is this what you are doing, or have you only tested at the turbo?

 

I have this mod (the UMW version), however, I did it when I upgraded injectors, LWFW and tuning to go with it, so I obviously gained power, unfortunately I did not have the time to be adding a mod and testing. My boost did not go up because I was already set up at the boost I needed to be for my fueling. Not sure how boost is supposed to increase with this mod. This mod allows turbos to spool up faster as there is little restriction, but how do you gain in pressure? Your pressure limits are already set. I would think tuning or ebc will change your pressure not this mod. Definitely worth doing though for sure.

 

In most cases, you shouldn't gain boost pressure as its being regulated by the wastegates. What you are doing is asking the turbos to do less work to spool and maintain that boost level->lower shaft speeds->higher efficiency/more headroom, etc. I say in most cases because AMS saw a few psi of extra boost by adding the pipes but that was near 2 bar.

 

exactly, that is why I am at a loss about the extra psi

 

Depending on how boost is controlled you might see an overshoot as the turbos spooled more quickly but you guys are right - steady amount of overboost is odd. If it's an EBC controlling things it might need some tuning to control the "happier" turbos perhaps?

 

one thing is for sure, when you take off the factory unit you will be shocked at how badly it necks down to a small opening. Really horrible design. Probably good for stock K16, but terrible for anything more. Even the K24 cars should have had larger intakes from factory.

 

Fully agree and that along with intercoolers and Y-pipe are my next targeted mods. I KNOW I'm choking the turbos! Not sure what turbos they are but they can't be happy and swapping out those inlet pipes will make any turbo spool better and breathe I'm sure. the more options the better for this I think - bravo AMS!

 

I've been strangling my 18g's for 1-1/2 years now...

 

and you've been choking the chicken for many more than that.

 

What is that soft hose called? If I wanted to buy it myself? like the stuff UMW and FVD use?

 

PM me, I have some left over.

 

You can also check this company out.

http://www.airhand.com/subcategories/flexible-hose/

I bought some of the "RFH" 70mm hose for my TT vette turbo intakes and it worked very well.
They offer other styles, too, in case something else suits you better.

Just a suggestion.