Need some help about DP and more....
 

Ok well i have my 2001 monte carlo SS 3.8 with the top swap into SC and for some strange reason sometimes when i floor it the car feels like its not picking up the rpms then i let off the gas a little and the rpms go shooting up would this be an issue dealing with the down pipe and the front headers? Would it be that the air flow out is being restricted by the OEM downpipe and front header? If anyone can give me an insight on this prob. it would be much appreciated... i have been told i could be a seal prob. but im not sure... and input would be appreciated thanks again

When you say the RPMs shoot up, do you mean like free reving, or just that it starts accelerating like you think it should when you get off the throttle a little? What are the rest of your mods?

exactly when i say they shoot up i mean it starts to accelerate the way i should.... well only mods i have on my monte is cold air intake and msd wires.... so that why im thinking i might need to get the downpipe and zzp's ploggs to open up the throat of my monte so the air shoot out of there... i guessing is that there is so much air trying to get out at once and it is unable to do so thats why it wont accelerate till i let off the throttle inputs plz?

You might be knocking like crazy at WOT since you don't have any other mods. Do you have a way to scan for knock retard? If not, you should definitely be getting something to scan, like an Aeroforce scan gauge or something.

Headers would be the way to go. For the price of a plog and downpipe, you could almost have a set of headers which flow much better. Heck, you could find used headers cheaper than a new plog and downpipe.

Thanks for the input bro.... so this Aeroforce scan gauge were can this be found and for how much... thats another thing i need to do i need to add my boost gauge cuz i have no idea on how much boost im at right now car is still incomplet stupid economy blows i lost my job now everything is on hold

https://www.zzperformance.com/grand_...=878&catid=168

That's the gauge I'm talking about, and I think ZZP has the lowest price. It's not cheap, but if you consider how many gauges you'd need to buy to read half the stuff it does (you don't need to buy a boost gauge if you have this ;)), it's a pretty good deal. Not to mention that when modding these cars, you really need to watch for knock and this is IMO the best way to do it.

I would say don't drive too hard until you can scan for knock. With a top swap and basically no mods, chances are you are knocking pretty bad. Even with headers, I still knock at WOT. I would suggest throwing a colder t-stat and colder plugs on there if you haven't. They're cheap things to do that will help you out.

To me, this sounds like an actual engine problem- I certainly wouldn't go throwing mods at it. You have to figure the factory L67 doesn't do that with the same manifolds, and there are people making pretty big power on factory manifolds with a turbo setup- so its not like there is some restriction making the engine not accelerate properly.

As for the knock thing- the car most certainly has quite a bit of knock with the only real mod being an intake. However, even with a ton of KR, the car should still accelerate normally- just a bit slower than a car with no KR. I mean back in the day all kinds of people were sticking 3.4" pullies on their GTP's with few to no other mods (before everyone realized the crazy amount of KR they were getting and the concept of supporting mods)- and no one had problems like this.

I think the first thing I'd try to do would be to take off the supercharger belt and see if it accelerates normally, that could eliminate that whole system. If it still does it with no belt, the next thing I'd look at is the wires. MSD wires are not known for being all that great- I'd try putting your stock ones back on. If that doesn't work, you either should buy the aeroforce gauge or find someone local with a scan tool to watch what the engine is doing when this happens. I mean this could be anything from a bad tune to a fueling issue to a transmission problem.

What pcm setup are you using?

How is it idling? Sounds alot like a vacuum leak to me. Vacuum test it- should hold solid at 19-20 at idle. If it's fluctuating alot, it's probably a vacuum leak.

What MAP are you using? Is the issue occuring all the time, or only when the car is cold?

You need a tune for sure. My Monte's idle quality and driveability skyrocketted after a full tune.

Well it is ideling normally nothing out of the ordinary in my opinion the car is tuned but not sure it its tuned correctly im talking of taking it back to the guy that did it for him to check it. im not quite sure on how to answer ur question about my MAP how do i know which one im using? and usually when this prob. happens is when its been running for a while mainly on the highway going about 70 then floor it and no acceleration then if i let off the throttle about half way it starts accelerating normally...

Well, did you change to the new L67 one when you did your swap?

If he has a tuner, definitely have him go for a ride with you and run a scan on the sensors to see if anything looks out of the ordinary when it happens.

So there are times when it accelerates fine when you floor it, and other times that it does not accelerate when you floor it?

Also, I'd be careful really getting on it unless your KR is down- what kindof KR did you have after the swap?