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Boost strangely high for my mods?

kyle91

kyle91

New member
Alright my mods are in sig and yes the zzp downpipe with headers. (Modded it some to make it work with SD headers). Now to what I was saying, On a decently cool night around upper 60s yesterday, on my 1-2 shift at wot I'm seeing my boost anywhere from low 9s to 10psi and that is with the stock pulley still. I had my buddy using the Torque app and cheapo ebay obd2 that would cut in and out but during one wot run it stayed connected and saw a blip of 2 to 4* KR and peaked at 6*. Because of the poor connection I don't know where exactly the blip occured as it just wouldn't work to well but hopefully someone could at least explain why such the high boost with all of my flow mods?
 


All what flow mods?

The exhaust is one of the easy restrictions to fix. You still have the heads as a restriction.

Cool night means you had more dense air. Dense air means that you'll get higher boost numbers. Keeping in mind that boost is pressure that is unable to be processed through the motor.
 
In my sig. I have headers, Speed Daddy's. Are you saying those are still a restriction? The speed daddy's mate up to a modified 3in zzp downpipe and high flow cat to a 2.5in catback.
 
What I'm saying is..that exhaust is not a huge restriction in my opnion. Sure the front manifold and u bend do help hold us back. But if you can't process air through the heads/cylinders and you have nice cold air temps. You are going to have some pressure backed up in the LIM. We call that pressure boost.

That's not boost. It's unused boost.
 
BillBoost37 said:
All what flow mods?

The exhaust is one of the easy restrictions to fix. You still have the heads as a restriction.

Cool night means you had more dense air. Dense air means that you'll get higher boost numbers. Keeping in mind that boost is pressure that is unable to be processed through the motor.
Click to expand...

Does cool air actually increase boost? Sure its dense but it should still be at the same pressure, unless due to engine heat it gets heated to the same temperature as the previously warmer air by the time it gets to the blower.
 
Oh I know I understand all of that but I'm just wondering why I'm still around 10psi when I've removed most my restrictions for my regal. I was under the impression I should at most be around 8 because before any mods when I was stock I would see 10 under the same weather conditions.
 


I understand that every car is different but I haven't seen any drop in boost really. Could it be that I'm revving higher at wot shift? Before on stock it was about 5600 with 10psi and now I'm at 6000 at 10psi.
 
revs = valve float, decreased VE (aka decreased exhaust flow through the head) and increased air incoming via the blower.
 
Okay I was sort of thinking about valve float at that high. Scott you think we could meet up any time before I head out to Kalamazoo to do any scanning? Possibly this Sunday since I'll be up in Grand Blanc to get my mps on?

To stay on track, so you think maybe backing off with a tune to say 5800 would maybe help get rid of some valve float? Plus I get this nasty knocking sound at wot 1-2 shift and just not sure what it is. UGGHHH I hate diagnosing problems.
 


Well the knocking sound I believe is coming from a dead lower motor mount and yes I'm concerned about it. Sorry I'm here at work and trying to get other stuff done also I just failed to mention that also. The knock occurs during the shift as I watch the tach fall. Its just one hollow sounding knock that sounds more like 2 parts hitting than "actual" knock from the engine.
And if that works for you I'll make the drive as I need to get this car in decent running shape before I start classes.
 
kyle91 said:
FWI, res & u-bend delete, SD headers mated with custom 3in downpipe, 2.5in catback with turbomax muffler, autolite 104s, 180 t-stat, TPS tinkering, poly mounts, custom tune.
Click to expand...

Wrong spark plugs for a stock pulley, homie. Back it off to 605's and see how you do.
 


how would the colder spark plugs give me higher boost if thats what your correlating the issue to? And if you aren't, whats the issue with running the 104's? I'm leaving them in since I'll be doing the 3.4 most likely this weekend.
 
My stock pullied PAU likes TR6's...runs better on the NGK's than the Autolites. TR6's are there for the anticipated 3.4 swap. I'd like to resolve my burst knock issue first but that's isolated to false knock/tuning at this point.

NGK's were cheaper too. bonus.
 
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