ModAddict

I recenly sold my CT blower kit and it was installed on a CL-S 5AT rather than a TL-S like I had done. The owner called and told me his boost numbers are not as high as mine were. We walked thru all the possible senarios of what might be wrong, and everything checked out ok. This weekend he took it to the track and ran a 13.6 at 103 w/a 2.20 60. My best was 13.89 at 102.8 w/a 2.20 60. So at this point we agreed that everythig was probably as it should be and his CL was running as it should be, even though the boost numbers were slightly lower than what I had when it was on my car. When I had origionally installed the kit on the TL-S, it was seeing more boost than the other installs on other CL's.

Do you think the heavier car can put enough of a load on the blower setup to make it have higher boost numbers? Kind of like pulling a trailer?

Smitty

hmmm interesting....

The weight ratio numbers of the TL vs. CL are not dramatic, so I would not think that the extra weight would do that...

The gentleman who purchased your kit is running the same type/brand of gauges you had?.....There will probably be a number fo factors involved...The trick is to narrow them down to 1.

darrinb

very interesting, i'll see what scalbert has to say....

allmotor_2000

The E.T's indicate both cars are putting down about the same power. The different boost #'s are probably because of different boost guages - you have the full-sweep electrical guage that corrects for altitude, correct? Even if he has the same guage... a slight leak can easily throw off readings by 0.5 - 1.0 psi.

Just my $0.02!

ModAddict

The gauges are my old ones including the tubing, tee, and he connected it at the same spot. When I showed up with the new S/C kit and ended up with 1psi more than the other CL installs,..I thought maybeit was my gauges. But now the actual set-up, blower and gauges, installed on a CL-S, shows up with boost numbers similar to the other CL's. So,....

allmotor_2000

Hmm.... what is the altitude difference between your area and the person you sold it to? If there is a difference, the boost guage will compensate.

scalbert

There are three primary possibilities with a blower running different boost amounts.

There can be variances between gauges but since this is the same gauge that is not relevant. However, gauge installation can cause a lower reading. If it is not sealed at the sensor you can get a lower reading. Also, if these are ratiometric pressure sensors, differences in system voltage can make a difference in the reading. What is the comparable vacuum reading??

Obviously the belt could be slipping a little which would lower the boost output. Does the boost hold steady, climb or drop throughout the rev band??

Lastly, boost stacking could have been occurring caused by increased exhaust pressure. A lower flowing exhaust system or even a slightly blocked exhaust (the catalytic converter) can cause the boost to increase. Does he have an aftermarket exhaust system? If so, that can lower the boost level.

ModAddict

Elevation is probably the same.

Not sure if they are ratiometric,... they are Autometer Phantom full sweep self zero'ing. He does have a sound system, and mine was stock. The vac readings were similar, but as to exactly the same I never paid much attention to the vac when I had it. I did suggest comparing to a mechanical boost gauge might show something.

The belt was the first thing i thought of, but a new belt and the boost is holding steady, so it sounds ok.

He does have an axleback, and I thought that alone, wouldn't make that much of a difference, but it seems to be a common difference to most of the other S/C'd CL's, and my TL.

If you hooked up a heave trailer, and pulled it up a steep hill, could that cause your boost to increase more than usual as your motor was fighting to get up the hill?

scalbert

It might a little but it would be minimal. The weight difference between the two cars is not enough to cause any noticeable changes to the boost though.

ModAddict

Well when he told me he ran a 13.6 @ 103, on his first run we figured things were ok with his install. The funny thing is, I think he's ready for another pulley already .

scalbert

BTW, what was the boost difference??

ModAddict

at peak, 2 psi

I was at a strong 7.5.

scalbert

And this is without the IMRC connected on both vehicles??

darrinb

i think its the belts slipping...

ModAddict

his is still connected

ModAddict

That's what I thought, but it's new, and tight.

scalbert

I doubt you saw 7.5 PSI with it connected?? Or did you??

I would only see about 5.5 PSI with it connected and a peak of about 7 PSI without it connected.

ModAddict

You know I don't really remember, but it was less. I'll ask him to disconnect it to see what that does for him.

Smitty

there is the culprit...

Is he running a different rim/tire set-up then what you had?..

darrinb

yea, brad has the stock 17's and flint has the 19x8 lowenhart br5's

flint

iTrader: (2)

I just put the 19's on. It was the same boost level with the stock wheels

flint

iTrader: (2)

The boost does not hold steady. It climbs to about 5 psi by 6000 rpm, and kind of fluctuates slightly between about 4.8 and 5 psi, until 7000 rpm, then spikes to 5.5 on the shift before it drops back to 5 again. The belt is new and as tight as I can possibly get it.

ModAddict

Well there's the new owner Hey Flint, disconnect the IMRC and see what that does to your boost numbers. Mine was disconnected.


I think Darrin was posting to the thread on the track times.

flint

iTrader: (2)

I might give it a try shortly

MtBikR

I've never had my boost exceed 5.5 and I have a 5at. I also run autometer full sweep electronics, and one thing I found is that they don't always self zero. A way to prevvent this, especially if you have a lot of them is to turn the car to the "on" position, without "turning it over". Give it a sec or two then turn the key all the way to start the engine. This gives them a few seconds to properly zero before starting up the engine. I do this every start now and no longer have such different readings expirences

darrinb

flint what are your plans with the blower from here??

flint

iTrader: (2)

Do you have the high boost pulley?

QUOTE]Originally posted by MtBikR
I've never had my boost exceed 5.5 and I have a 5at. I also run autometer full sweep electronics, and one thing I found is that they don't always self zero. A way to prevvent this, especially if you have a lot of them is to turn the car to the "on" position, without "turning it over". Give it a sec or two then turn the key all the way to start the engine. This gives them a few seconds to properly zero before starting up the engine. I do this every start now and no longer have such different readings expirences [/QUOTE]

flint

iTrader: (2)

I really haven't had much time to look into it yet. I'm not sure how much more stress I want to add to the engine as I plan to keep the car another few years and already have 60,000 miles on it. That being said......I am waiting for my new b-pipe to show up!

flint

iTrader: (2)

I tried disconnecting it. Got maybe another .5 psi through 3000-5000 rpm. After that boost settles in at 5.5psi until redline. The car felt slower overall but that is hard to back up for sure until I try it at the track or dyno it. In the meantime I connected it again and the car feels stronger down low but no change up above 4500 rpm.

scalbert

You sure you disconnected the correct plug??

The IMRC is closed and does not open until about 4k revs. So there is no difference with it plugged in or not below 4k revs so the boost should have been the same. Power should also be identical below 4k revs as it is closed regardless.

MtBikR

No I missed that sorry, stock comtech pulley on now.

flint

iTrader: (2)

So I am running the same boost as others with the stock pulley. i am going to check my gauge's vacuum lines next to see what i come up with. Disconnected the IMRC again tonight to double-check. After about 10 runs through 1-2 and a few runs through 3rd with it connected and disconnected, I can say there is virtually no difference. As mentioned above boost is identical through the lower part of the rev range. Watching closely, I do gain maybe .5 PSI on top but that still only peaks at around 5.5 psi and slightly higher (still not making 6 psi) with the IMRC disconnected. Also watching closely, the boost will actually dip slightly between 6500 rpm and redline and spike back up on the shift. This can be because the belt is slipping (I don't see how) or my engine is flowing air so well at that rpm the s/c isn't keeping up (which I also doubt). The boost is more constant with the IMRC disconnected. It has more of a tendency to drop slightly between 6500-7000 rpm when the IMRC is plugged in.

ModAddict

Leave the imrc disconnected for good, and tighten the belt one more time. If I remember correctly, the specs say torque the tensioner to 25 ftlbs. Try 35 ftlbs, tighten the two clamping bolts, then re-torque the tensioner to 25. Is your air cleaner clean,....

Good ground on the gauge???

Smitty

I would watch out tightening that belt too much, you can easily bend that Shaft!!... it has been done before..

ModAddict

Bend the jack shaft????

scalbert

We all found it was more consitant and didn't make a significant difference in power with it connected or not. My car made 315 WHP without it connected and then made 323 WHP with it connected but there was audible knock. When tuned by adding enough fuel to compensate the power was back down. Regardless, I'll give up 2.5% power to keep knock at bay.

scalbert

In addition, I found a slight lull in power at about 4200 RPM with it connected. Without it the power was more linear.

scalbert

, bend the jack shaft???

Smitty

Yes, bend the jack shaft....

You both should already know that.... I dunno if that extra 10LBs of tightness will bend it, but you got to watch wrenching on it.... it spells disaster if you go bannanas on it.

scalbert

The aluminum threads for the tensioner pulley would strip well before that shaft bends of even distorts. Especially considering the support point at the very end.