More boost with Perrin TM added?

**KTM 525** · #1: 10-15-2005, 05:20 AM

Last week I was out with my AP hooked up reading live boost. I started a thread on it. I was seeing about 16.9-17.0PSI as peak numbers in 3rd and 4th gears.This was with the stock TMIC. I installed a Perrin TMIC and ran into some issues with the boost tube (tube from the TB to the IC. I had to use a makeshift tube that did not fit right and was a bit restrictive. After the install I was seeing about a solid 1/2-3/4 pound more PSI peak boost (17.6 area).
I figured this was from the makeshift boost tube being restrictive. I figured if air cant pass from the turbo through the IC as freely the added buildup would result in the higher numbers I was seeing. Well I got a new factory boost tube and installed it. I am still seeing the same peak boost numbers. Does this sound possible? Where does the ECU get it's boost readings at? If it's after the IC then would'nt a restriction before the IC get result in lower boost numbers? This would actually make my theory of the restrictive boost tube getting me higher numbers in the first place false. Dont get me wrong I would not mind the higher boost numbers. I am just afraid here something is wrong. I just cant see what it could be. The install is pretty striaght forward. Thanks for any input.

**John M** · #2: 10-15-2005, 12:23 PM

The ECU reads boost in the manifold from a MAP sensor on the front of the engine near the alternator. It looks like a solenoid w/ a vac line going to it. It's the one with a filter inline w/ the hose. These hoses have no clamps from the factory so you may want to add some yourself. I don't know why Subaru doesn't clamp their pressurized hoses when every other manufacturer does.

**rony** · #3: 10-15-2005, 02:30 PM

I got a custom protune yesterday, and one of the warnings the tuner (Jorge) said, was that I needed to clamp and superglue the BOV tube to be safe. He had at least 2 legacys pop those tubes when pushing them to 18 psi of boost. Btw, I'm refering to the T connector under the TMIC where the BOV connects to the manfold.

Btw, I pulled the intercooler and did what he said while he was flashing a base map to my car for the tune.

**KTM 525** · #4: 10-15-2005, 06:00 PM

So does an inrease of 1/2-3/4 pound of boost from adding a TMIC seem logical? "if" there were a restriction before the Throttle Body the ECU would read less peak boost then? I just want to be sure nothing is wrong here................ Seems to run fine any hoses popping off would result in a vaccume leak and I would not see 20hg at idle right?

**KGreb** · #5: 10-15-2005, 08:36 PM

The Perrin TMIC core has less pressure drop than stock. Because of this the turbo should make a little bit more boost if running the same boost control solenoid duty cycle. .5 - .75 psi sounds reasonable, but could also be partly due to colder fall weather.

**KTM 525** · #6: 10-15-2005, 08:43 PM

Quote:

Originally Posted by KGreb

The Perrin TMIC core has less pressure drop than stock. Because of this the turbo should make a little bit more boost if running the same boost control solenoid duty cycle. .5 - .75 psi sounds reasonable, but could also be partly due to colder fall weather.

Thanks for this info.

**driggity** · #7: 10-17-2005, 12:02 PM

When I switched from the stock TMIC to the Perrin I picked up almost a pound of boost. This was comparing runs that were made the same evening so the weather didn't change much between them. At the time I had an catless up-pipe and downpipe and stock engine management. After the ECU did some learning the peak boost seemed to get closer to what it had been before the Perrin IC install, but I only ran that setup for a couple of days before I got an ECUTek reflash.

**jim1969** · #8: 10-21-2005, 05:35 PM

Quote:

Originally Posted by rony

I got a custom protune yesterday, and one of the warnings the tuner (Jorge) said, was that I needed to clamp and superglue the BOV tube to be safe. He had at least 2 legacys pop those tubes when pushing them to 18 psi of boost. Btw, I'm refering to the T connector under the TMIC where the BOV connects to the manfold.

Btw, I pulled the intercooler and did what he said while he was flashing a base map to my car for the tune.

any pics of how you clamped it?

**rony** · #9: 10-21-2005, 10:36 PM

Quote:

Originally Posted by jim1969

any pics of how you clamped it?

Nope, but simple...

A drop of super glue and a zip tie, I know getto, but I didn't have a ribbed T connector to replace it with.