Quick question for those with an Autorotor CTSC and boost gauge

[Matt_337]

In the past, I have seen my boost gauge read over 7lbs of boost with the Autorotor CTSC. What is the most amount of boost that you guys have seen with just the Autorotor CTSC bolt on (no AEM or other EMS)?


The reason why I ask is while I was at the track this past weekend, my instructor noted that he saw just over 8lbs of boost on my gauge at WOT (I have the SPA digital gauges that SoS sells so it is easily readable).
Has anyone else ever seen this? I know it's hard to look at the gauge and drive.

 

[S-TO-8K]

I'd be curious to see some replies here too...

 

[ryan1926]

When my car was on the dyno at Comptech, the max boost they recorded was 6.8lbs. I used the record and peak function on my Defi BF gauge and the gauge read closer to 8lbs. So I am assuming that there is some error with regards to the reading on the gauges.

 

[Matt_337]

Since we both have different gauges, then what is the point in having a gauge to monitor our stuff if it is this inaccurate?

 

[ryan1926]

Since we both have different gauges, then what is the point in having a gauge to monitor our stuff if it is this inaccurate?

Perhaps to capture any extreme failures??? I didn't read the technical specs on my set of gauges, but I wonder if they have any +/- error stated.

 

[Matt_337]

I just found SPA Designs website and was reading up on the dual gauges that I have.

I copied and pasted this part:
"SPA Design provides a wide array of dual gauges that provide the user and operator with specific and highly accurate information."

Being off by over 1 lb of boost should not qualify as being highly accurate information in my book.

Here is their link:
http://www.spa-uk.co.uk/design/dualgauges.asp

 

[croni]

Matt,
I am confident it was nothing more than the cold dense air conditions on Saturday. Wait until the summer to see how much boost you loose due to the heat.

 

[MiamieNeSeX]

Ambient temperature differences can cause boost levels to read both high and low.


Armando

 

[ryan1926]

Ambient temperature differences can cause boost levels to read both high and low.


Armando

True, but I am curious why on the same dyno run Comptech measured 6.8lbs and my gauge recorded a peak of close to 8lbs.

 

[SaberX]

I have an autorotor and SPA boost gauge as well. I always see 8psi of boost at WOT and high rpms. Using the peak recording feature of the SPA gauge I have seen 13psi listed as the peak. I spoke with some people about it and since it's an electronic gauge tapped right into the plenum it seems likely this is just a boost spike caused by pressure waves under certain conditions. (I've also never seen the screen read 13) I also saw close to 8psi recorded by another mechnical sensor when I dyno'ed it.

 

[annointed]

One of the lessons that I remember from Corky Bell's book "Maximum Boost" about turbocharged systems (more applicable to me, since I've owned 8 turbocharged performance cars now, but zero supercharged cars...and yes, I understand that a turbo is technically a type of supercharger:tongue: ) is that the boost gauges will read different psi levels depending on exactly where in the intake tract they are plumbed into, particularly if you're running an intercooler (or other components that have pressure drops across them), which I assume you're not on a low boost CTSC. Nevertheless, its very likely that the boost readouts that are contradicting one another have different plumbing orientations. I've also had wacky boost levels recorded by "peak hold" features of electronic boost gauges/boost controllers, as several of my cars had multiple boost reading features (ie, laptop/datalogging via standalone engine management vs. electronic boost controller vs a mechanical gauge, all in same car) and they rarely read the same levels.

 

[Matt_337]

Just to resurrect this thread, I drove the car this past week and while the temps were fair and not low (mid-70's), I got on the gas and then saw my boost gauge blinking. I looked down and it was reading over 9 lbs (I have just the regular autorotor low boost kit).

I know people are saying that the boost reading will be different based on where it is located along with the colder air, but this has me worried. In any case, when I get my car back from my mech (getting some more stuff installed), I will take it to a dyno again to see what the real readings should be when my gauge says it's over 9.1 lb. I just don't feel comfortable getting on it.
Am I worrying over nothing?

 

[MiamieNeSeX]

Just to resurrect this thread, I drove the car this past week and while the temps were fair and not low (mid-70's), I got on the gas and then saw my boost gauge blinking. I looked down and it was reading over 9 lbs (I have just the regular autorotor low boost kit).

I know people are saying that the boost reading will be different based on where it is located along with the colder air, but this has me worried. In any case, when I get my car back from my mech (getting some more stuff installed), I will take it to a dyno again to see what the real readings should be when my gauge says it's over 9.1 lb. I just don't feel comfortable getting on it.
Am I worrying over nothing?

A mechanical boost gauge temporarily tapped into the vaccum line, run the line into the cabin and make a few runs, might be your boost gauge is off by a bit.

Armando

 

[SaberX]

Just to resurrect this thread, I drove the car this past week and while the temps were fair and not low (mid-70's), I got on the gas and then saw my boost gauge blinking. I looked down and it was reading over 9 lbs (I have just the regular autorotor low boost kit).

I know people are saying that the boost reading will be different based on where it is located along with the colder air, but this has me worried. In any case, when I get my car back from my mech (getting some more stuff installed), I will take it to a dyno again to see what the real readings should be when my gauge says it's over 9.1 lb. I just don't feel comfortable getting on it.
Am I worrying over nothing?

This weekend in Seattle it was mid-70s and I filled up using premium and I didn't bother to put in a bottle of octane booster because I figured it was warm enough. I was wrong. My car was making 8.5 lbs of boost and detonating under load while the motor was hot. :-(
However, after a bottle of Lucas Oil octane booster the pinging went away. I spoke to Shad about this a while back and he basically said that there needs to be different fuel settings based on temperature with the new Autorotor boost setup. At the moment he is the only person capable of doing this... perhaps a group of us with Autorotors could chip in and cover the R&D cost to Shad? If I have to spend $10 per fill up on octane booster, that's going to add up pretty fast and I would much rather spend a few hundred now to get the problem solved! Any thoughts?

 

[DDozier]

This weekend in Seattle it was mid-70s and I filled up using premium and I didn't bother to put in a bottle of octane booster because I figured it was warm enough. I was wrong. My car was making 8.5 lbs of boost and detonating under load while the motor was hot. :-(
However, after a bottle of Lucas Oil octane booster the pinging went away. I spoke to Shad about this a while back and he basically said that there needs to be different fuel settings based on temperature with the new Autorotor boost setup. At the moment he is the only person capable of doing this... perhaps a group of us with Autorotors could chip in and cover the R&D cost to Shad? If I have to spend $10 per fill up on octane booster, that's going to add up pretty fast and I would much rather spend a few hundred now to get the problem solved! Any thoughts?

If a bottle of Octane boost cures your pinging, then you are way to close to the edge on your tune, talk to shad again and see if you can bump your fuel pressure up a pound or two at idle, you will run a little richer throughout the range but remember the effects of detonation are accumulative each one will weaken the pistons until the last one breaks the ring lands then its rebuild time if you are lucky and new motor/heads if you are not.

I am not trying to scare you but, this is serious enough that you should not be driving the car hard until the issue is resolved.

Dave

 

[Alan C.]

If you read the label on most octane boosters you will find they something like: Adds 1 -2 points. The points they refer to to are decimal points ie. .1 - .2

On my 944 turbo GT3S the intake manifold was drilled and tapped on all 4 intake runners. A line from each was plumbed into a small cylindrical tank. I ran my boost sensor out of that tank. In that way I had an average of all 4 intake runners.

 

[nsxotic911]

This thread got me wondering about my setup.....I have the High Boost Whipple w/ AEM and tuned by Autowave- and my Defi Boost gague reads WOT at about .8 bar, with the 'peak' at over 1.0 bar..eek

The conversion of .8 bar & 1.0 to PSI @ 350 sea elevation is...11 PSI & 14 psi.
(http://www.dragsource.com/index.php?navselect=calculators&calctoview=8)

I'm not sure if I should be scared or not... It was tuned in LA and I'm in Seattle so the weather & elevation is a bit different( 350 vs 330 as per: http://www.idcide.com/index.htm) nonethelss not that much off. I can't imagine that Autowave tuned it for 10+ psi ??? Unfortunately, this was done over 2 years ago so there is a certain level of Amnesia with Autowave when I inquire about the details...

I don't know if I can trust the gauge though based on what's being said here, and it was my understanding that the Whipple's were less efficient and the "high boost" really tops out more like the Autorotor low boost of 8.5 PSI. I don't believe I've had pinging and I've been told that the map has the car run *real* rich anyway; the gas is also better here/higher octane.

Recent fouled pluggs with fuel/carbon seems to support that. Though letting it idle for 30 minutes a number of times was also a factor.

Engine feel strong, recent compression check came in at 200+ across all cylinders.. nonetheless, the car seems to not run as strong when it's cold - maybe b/c of timing retardation & higher boost or the fact that it wasn't tuned for 32F- weather?

I don't have a wideband so I can't see the A/F though plan to get one... Earliest I can get it down to Rev Motorsports in Portland is end of next month..

Thoughts?