Hey guys,
I've got the mods listed below. Anyways, i just got a magnum powers charger and got to talking to the boys at JDM. They seem to think i need to scrap the stock exhaust and open it up to help relieve the pressure on my stock block due to the restrictive exhaust. The mods and tune i was going for should put me at about 450 horse (hopefully). I don't want to go past 450 for now but if i do ehaust i think it will take me closer to 500. My questions are:
1. do you think running aftermarket exhaust that creates more horsepower will be safer for my stock block than a restrictive exhaust with less horsepower?
2. By opening up the exhaust do i only need to take care of the cats or are the exhaust manifolds pretty restrictive as well.

i was thinking of possibly running a 2# instead of the 4# lower since the magnum comes with a 2.70 upper then putting on the exhaust and that might put me close to 450?

What do you guys think? Thanks for helping me out. You all seem to be able to shed light on all problems. Thanks.


Mods are: (2000 lightning)
Bts trans, PI converter, 90 mm maf, magnum charger,
4lb lower(currently), boost bypass, CAI, 160 stat, tr-6's, e-fan, 2002 intake and intercooler, predator, l&s separator, t-bars

 

Why not just finish up on what you've started and see if you're happy with the results?

Exhaust parts can be expensive considering the gains seen by many on this site.

 

Sure you'll see higher HP numbers..

However I think it comes down to how you use the truck. If it's a only a cruiser & 1/4 mile drag toy? Then place your order.
If it's a daily driver and/or a 1/8th mile toy? Then you'll wanna keep that low end torque offered by the *somewhat* restrictive stock exhaust.

Rich

 

This is a very appropriate question for me as well.

I am putting a MP on mine, as well as a 4lb lower. I was thinking about ditching all four cats to lose a bit of the restriction. Anybody have sound clips of factory manifolds, no cats, and a magnaflow catback?

With a 4lb lower and the MP blower which comes with a 2.7" upper, how much boost will we get with stock manifolds?

 

You wont regret getting a full exhuast system on your L.
kooks + bassani > kooks + magnaflow

 

all engines are air pumps.
the more air that it can pump through, the more power it will make.

So if the flow is bottled necked somewhere, then you are losing power.

open up the exhaust will allow more air to flow.

 

Oh yea, I already have the bassani cat-back and now I just recently order long tubes and high flow cats from JDM. My beast is going to roar.

 

Just ordered the new beta version of the bassani, custom made full exhaust.

my tuner knows the owner of bassani so I'm #2 in line.

its a 30-45 day wait but I hear it's supposed to be wild.

Everyone pray it works as well as I hear

 

Really the question i need you guys to help me with is:

Am i more likely to break my stock block with 450 horsepower and a restrictive exhaust then i am with 500 horsepower and an opened up exhaust.
JDM has told me that the pressure exerted on the rods due to the restriction of my stock exhaust is too high and must be remedied imediately. Like i said before i would like to be sitting at around 450 horsepower with a conservative tune. Just to be safe so the stock block can live a little longer. Thanks guys for all your help.

Oh yeah and if i do the exhaust i was thinking of just gutting the cat and installing a new muffler and leaving the exhaust manifolds as long as they are efficient enough. Do you think the stock exhaust tubing is of sufficient diameter to support 450 or 500 horsepower. Thanks again.

 

On the top end. Yes. Down low *NO* it won't, you'll loose low end torque. Cylinder scavaging isn't as good when the velocity exiting the exhaust port is lower. Like when loaded at low rpms.


No. However both those power levels on a stock long block is quite substancial. Make dang sure the tune is good. And where does the 50hp come from?

Your combustion & exhaust gas temps would be lower & the heads would be able to flow a bit better on the top end.

As far as added pressure... the amount of additional "pressure" is small in comparison to things like detonation. Which....? may be what your vendor is trying to tell you? But in a generic manner. (open exhaust would be a bit easier in preventing detonation)

BTW, the free flowing exhaust comes mostly from the high flow cats.

Rich

 

That's kinda what I thought, and the main reason I was thinking about losing the cats.

Anybody got any exhaust clips of stock manifolds and no cats?

 

The downside to the full exhaust is the noise and the dollars spent.

The upside is lower boost pressure and more HP.

I already had several mods on my truck when I went from a single Magnaflow to a full exhaust with a single Magnaflow. It felt noticabily stronger (more responsive) when I stepped on the gas a little at lower RPM cruising speeds. My 1/8 mile and 1/4 mile ET's along with MPH were better. This is fact not opinion.

How could it not be safer on a stock block? It should lower your boost pressure by 1 to 1 1/2 pounds. This would make you less likely to detonate and less likely to stretch the factory (torque to yield) head bolts lifting a head.

I'm sure your tuner doesn't mind selling you a full exhaust system but what he is telling you is not BS.

 

There really are too many factors to account for. Doing nothing else but the exhaust would result in a leaner burn. More power measured would come from more energy being released during the combustion. Put's it that much closer to the edge.

but keep in mind it's all relative to many other things. The tune being numero uno.

BTW: 1/8mile speeds are not a mesurement of low rpm torque. And that is a FACT.

Rich

 

Mine is a daily driver that is over 4 years old with 53,000 miles. The full exhaust has been on for over 2 years. There were no weak spots that could be felt in daily driving. It felt stronger EVERYWHERE. This is a FACT.

BTW, You mentioned daily driving and 1/8 being a negative. I was just responding with my experiences.

Peace

 

wouldn't less back pressure result in less boost?

Correct on the more power on the top end but not the low end (forgot about that)