I just recently installed a Catcam 469 and the car pulls like a freight train from 4K up. Now I’ve been running with out a cat for some time and my boost it right at 18 psi. Now after the cam install the car got way louder to the point I have to shut it off at drive throughs so I decided to put the cat back on. Brought it back down however my max boost is only 14 psi. The whole exhaust is Miltek and the cat you can look right through it. Keep in mind when I was running with the cat before I was also seeing 18psi. I don’t know what caused this??

 

Did you notice your boost after you put the cam in, but before you put the cat back on? My understanding is that boost can/does go down when the head flows better (or the valves are open longer) because boost is affected by the amount of resistance to air flow. So it wouldn't surprise me that your boost number would go down after the installation of the cam, and if your cat is a high flowing cat, it shouldn't make much of a difference. This would be confirmed by the car still running well and making more power with lower boost, because more air is making it through the engine rather than getting pent up in the intake manifold.

 

That makes lots of sense however I was still getting the same boost after the cam install. However I had the tune revised but minor and then installed the cat. After that is when the boost was down. The cat is a Miltek high flow and new and with these r53s all boost is maintained by mechanical means so I don’t know what changed?? Today I checked my vacuum lines and intercooler boots and all was fine. I still am having trouble with the car dying when coming to a stop though.

 

Sure sounds like you have a vacuum leak especially since you're having troubles with idle. Have you smoke tested it? You might also check your S/C boots because they often kink on the bottom side when removed and reinstalled.

 

it’s not the idle that I’m having problems with it’s when coming to a stop, the idle drops down but sometimes regains itself. It will sit there all day and idle nicely. Also noticed on the boost gauge that it will just about hit 30” of vac on de-acceleration 2000 rpm but bounce back up to about 15” at idle. Never did that before.

Yes checked the boots and vacuum hoses today. I might smoke test it tomorrow but was looking today where to stick the probe… map sensor on the intake?

 

Any codes?

 

none.

 

I have heard running the 469 cam is hard to tune ?

 

I'm just here to ask how you got a m45 to 18psi, 20 % pulley?

 

Yeah........something doesn't sound right.

 

using a 16% pulley and a 2% OD crank pulley

 

Who did your custom tune? It could be something simple like that, as far as it not wanting to come off of WOT and idle right.

 

Adrian from Germany

 

does not compute, unless your cam was off by a tooth or exhaust was plugged that's more boost than you could possibly have

 

I’m not going to argue with you I’m telling you what it has been for a long time and now what it is. Exhaust is not plugged and cam is not off by a tooth

 

Well that's good cuz I wasn't arguing I was stating a fact

 

Are you running a stock cam or the 469?

 

I've run five different cams over the years neither of my r53s are on a stock cam or a 469 right now.

That cam is a little more aggressive than a ph2 you're not going to have boost that high unless something is wrong

 

ok here are the facts… I have all the mods except a BVH and before I installed the 469 I was running a RMW 250 cam and getting 18 psi of boost at 7000rpm with no cat. Week and half ago I installed the Catcams469 with the tune I already had and drove it for a week. Still getting 18 psi of boost and pulled extremely strong from 4K. Last Friday I got a hold of my tuner and asked him to double check everything and change what needed to be done. Up to the point the car only died once on me coming to a stop. Also I decided to put the Miltek cat back on due to how loud it was going through drive through. Now I did not drive the car after I put the cat on however I started it to hear the difference. That night the tuner made some changes and Saturday I took it out still running strong but maxes at 14 psi and now the car will die coming to a stop unless I let the clutch out slightly and the idle will regain. That’s the facts and that’s what I’m trying to figure out. If 18 psi is out of the question why has it been that over a year and now it’s 14?

 

Are you using an analog boost gauge?

 

it’s a Marshall analog

 

I haven’t checked but thought maybe the throttle plate is not opening all the way, throttle body related with his tune??

 

Do you have the ability to data log? These engines will reduce torque by reducing throttle input AKA close the throttle body and lower air amount going into the supercharger which lowers your boost

 

yes but I don’t know how to use it the tuner installed it Friday night and I just followed along. He had me bring the rpms to certain levels.

I have data loved in my truck ( different of course) but actually had to drive it to data log but with him I didn’t

 

What would cause that then? I have also noticed I’ve had to feather the throttle because it wouldn’t go like there was no input. That even happened today leaving my driveway.