Hi guys!! I´m currently doing a custom tune, and doing some logs on the road, and we think the car has a boost leak because we are only seeing 11.5 PSI of MAPpsi at 5000RPM, are these normal values for my mods?

-SparkPlugs NGK Iridium BKR7EIX
-Panel K&N Filter
-Intercooler GRS Black
-17% SC Pulley
- Stock Head
-Cam Newman PH2 250/400 (I believe its also known as RMW Dominator CAM)
-Injectors Bosch 550cc
-Stock headers with both stock pre-cat and cat
-CatBack 63.5mm Direnza non resonated

I would really like to know what kind of values are you guys doing with similar mods before starting the search for some kind of boost leak or belt slipping.

Thank you so much, any help is appreciated.




3G Pull to 5500rpm

 

The GRS intercooler alone probably shrink the psi numbers a bit since it's much larger than stock and the supercharger push the same amount of air, but has to fill more space.

 

Hi Ghost, ty for the reply, thats what i thought but even with the IC shouldn´t it be a little closer to 14ish psi?

Thanks

 

Yea, don't agree DaGhost.
While the larger volume of the cooler will cause a slightly longer time to "get"...to pressure, the engine is still the plug and with a "plug" in the system, full pressure should still be achieved at a given rpm.
Like I say, it may just take a second or so longer to get full pressure. I'd still expect at least 12+ / 13 lbs. with that intercooler.

But I do not know about the cam spec's. If the new cam's duration or overlap is longer than the stock cams spec's...THAT will cause the pressure to be low.

Mike

 

If its this intercooler, no these boost levels not normal. These top mounted intercoolers like most aftermarket and DFIC style its more of an issue of not being able to direct the air flow as well as stock, and recovery time after heat soak.



Thats a significan boost loss.
I have similar mods sans the cam and pushing 17-18lbs all day.
I would use a quick tie to secure the BPV in a closed position.
Then see what happens....

 

I'm not sure how the Newman cam acts, but if it's anything like the catcam, I'll say it's that.. Since installing my catcam my boost readings have been weird and lower than before.

 

I have not quick tied the BPV yet, but I did the hand test to see if it had good pressure and if it would bounce back and seemed fine

 

My belt tensioner is on its way out, it squeals for about 2 min on the first start of the day then it shuts up.
I already ordered a gates one, do you guys think it might be the culprit?

Also attached cam specs if it helps.

Thank you for the help guys!!! Really appreciate it

 

If your belt tensioner is on its way out, this is lore than likely the culprit as you will have belt slip especially at higher rpms.

 

I'm hoping that it is the problem, I ordered the gates tensioner, the idler pulley and the gates 6PK1360. Hoping to at least pick up some of the lost boost with that.

Thank you for the help, I'll update when the repair is made.

 

Uploaded 2 pics, 1st is my own belt tensioner (No hole in sight) and second is how its suppose to be, pretty sure the new tensioner should do it, got a p1688 code aswell but no limp mode, and the crank pully was replaced not long ago

 

Yea that is looking very weak. Replace the tensioner. They all need replacing at some point. Hope that resolves your issue.

 

It may not be tesnioners fault.

When was last time the actual belt was replaced?

A worn stretched belt expands reducing tension on the tensioner resulting in the strap showing less hole(s).

 

the belt is pretty fresh compared with the tensioner, i think the belt has 10k on it

 

Replace both if you are able to

 

Sorry for the long delay, just replaced all pulleys and belt and got about 1 more psi throughout the range of rpm, still think its low :(

 

What max boost do you see at max rpm? Initial post said 11.5psi at 5000rpm...so I take you at 12.5psi there now and at max?

 

12.9 Is the highest MAP value I have seen...

Yes 1PSI gain through the rpms, and i get boost much sooner that before the new tensioner, pulleys and belt

 

Hi guys, I´m sorry for digging up my own thread again.
But i´m yet to solve this problem!

Today I installed a detroit tuned BPV, I gained about 0.5 PSI across the rev range but unfortunatly the problem continues.

I get Peak Boost (13.4PSI) at 5600RPM and then the boost goes down to 12.3 and stays there till the rev limiter.

I dont know where to find the missing boost, with a 17% pulley i should be pushing 16 PSI.

Any ideas where to turn to next?

Already did belt, tensioner, BPV, IC Boots.

Any help is apreciated





As you can see after 5600RPM where I hit 13.5PSI the it drops to 12.4 and stays about there till the end

 

Even with a semi-agressive cam I would expect some boost loss due the efficiency of the air flow with the Newman Cam you put in, and even more with a free flow cat/header. What sort of HP/TQ numbers are you seeing.

 

Haven't dynoed it yet, but should be around 230

 

At idle is the boost gauge reading a steady 18-20inHg ?

If so I'm going with what you are seeing for lower boost is due to your air pump ( engine ) flowing air more efficiently reducing back pressure to the forced induction unit ( supercharger )

 

At idle im reading steady 16-17inHG

Yeah i agree that that is a factor but shouldn´t the boost increase all the way up till the rev lim?
Should it be peaking at 5500rpm?

 

No your right, boost should probably continue to climb up to 6500 or 7000 depending on your tune setting.

And that low at idle I'm thinking maybe boost leak as that is a good way to gauge that....maybe cracked line for the FPR from right side of horn ? My last boost leak I found to be missing metal gasket at left side supercharger horn....

Who did your tune ?

Bytetronik has some experience with modded R53's, Bytetronik maybe he can chime in.

 

I'll Check the FPR lines!

Adrian CL tuned my car