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98 Sub Upgrades

SUB602

1/2 ton status
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Jan 18, 2007
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PHX, AZ
Today UPS is delivering my Flowmaster Cat-back exhaust I ordered from Summit Racing. I actually ordered it about 1 month ago, but they shipped me the wrong part. They sent me a single cat-back instead of a dual Cat-back. Either way it will be here today and will be installed by the weekend. Besides installing a SSBC front brake kit this will only be the 2nd upgrade i have done, and i cant wait to hear how it sounds. Keep ya posted!!
 
I really like the Flowmaster sound. I think they hurt fuel mileage though. I cant keep from mashing the go pedal to hear that sound.
 
lugnut said:
I really like the Flowmaster sound. I think they hurt fuel mileage though. I cant keep from mashing the go pedal to hear that sound.



Yea i am sure gas mileage will suffer a bit cause i know i need to hear that sound as well, but this thing cant get out of its own way so i am trying to free up some horsepower. Future plans call for Headers, Intake system, and a Power Programmer. So we will see how it all comes together.
 
Installed Exhaust System yesterday. I still have parts of it clamped together. I have to finish welding it in place. Probably do the welding early Saturday due to the heat in the garage being at about 120 degrees. Huge improvement in power and acceleration though. I usually roll my gas pedal to get moving from a dead stop. Before installing the exhaust system the Sub would take forever to come to speed. With the new exhaust installed it comes to speed alot faster. Noise factor inside cab has increased, but that was expected. Overall The Cat-back Exhaust system from Flowmaster is a wise investment for any Suburban in my opinion.
 
Installed Exhaust System yesterday. I still have parts of it clamped together. I have to finish welding it in place. Probably do the welding early Saturday due to the heat in the garage being at about 120 degrees. Huge improvement in power and acceleration though. I usually roll my gas pedal to get moving from a dead stop. Before installing the exhaust system the Sub would take forever to come to speed. With the new exhaust installed it comes to speed alot faster. Noise factor inside cab has increased, but that was expected. Overall The Cat-back Exhaust system from Flowmaster is a wise investment for any Suburban in my opinion.

Hows the long term on it ? Mileage , and how its holding up . I am DD a 99 now , and the stock stuff is already welded back up once , and gots to go :D
 
Yeah, how's the Flowmaster holding up? I'm planning on a 2-in 2-out 70 series muffler for my Yukon this fall. I want it to be quiet at idle and part throttle, but loud when I mash it. Mines the same way stock, sluggish and slow to get to speed.
 
I have no complaints. The Flowmaster system works very well IMO. Interior noise is minimal, and when i get on it she roars pretty good. Its exactly what i was looking for. Power on take off is like night and day. As far as mileage last time i checked it was around 20 MPG. Keep in mind with gas prices the way they have been i am very light on the throttle these days. Not to mention i only work about 5 miles away from home. 2 thumbs up :waytogo:
 
I just did this , kinda . Scored a two in two out Flowmaster from 4xcrazy . One two into one connector from MaxPF . And I reused the mandrel bent 3 inch stainless tailpipe . Sounds sweet an it improved the vroom vroom .

I love the fact my Sub came dual front tubes from the factory . Just wish I had more room for dual pipes out the same side like the pickups , for that sleeper look . We did try the dual pipes from my 93 pickup , but with the gas tank and the swaybar , it did not play well once lowered off the jackstands .
 
Cool i hope it works for ya. I still cant complain about my Flowmaster system it works great. The best upgrade i have done on my Suburban. Still want to add some headers and an aftermarket intake, but i have been too busy on the Blazer and really havent done too much to the Suburban lately.
 
I totally forgot about this thread. I love the flowmaster on my Yukon, I posted a vid when I got it put on last winter. Really gave it more pickup and even increased the fuel economy by close to 1 mpg. I'm happy with it now.
 
Since i have been working on my BLazer i have kinda neglected the Suburban. Sorry i did that!!

This weekend took the family camping near Payson, AZ, and at one point i could only go 40MPH climbing a hill. I tow in 3rd gear and only go into Overdrive when running flat. It was my Suburban family of 5. Myself, my wife, 3 kids under 7 years of age, all our gear in the back including a Utility trailer filled with tent, tables, firewood. I saw the same size Suburbans pulling Travel Trailers.

So know i am looking to get better pulling performance. Was thinking of doing a rear end swap to a 14BSF, or changing the gear ratio in the O.E. rear end, aluminum finned higher capacity Trans Pan to help reduce heat.

Any ideas on what can help me get better performance when Towing?
 
What gearing is in there now ?

My 99 has 3.73;s and has no trouble with towing a truggy . I would probably be lugged down to 45 on some of those grades .
 
What gearing is in there now ?

My 99 has 3.73;s and has no trouble with towing a truggy . I would probably be lugged down to 45 on some of those grades .


would that info be in the VIN or tag in the Glovebox?
 
3.73 gears with a posi- limited slip.
So maybe try to get more power from the motor? Can really do much more than Headers, and an high flow intake.
 
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It's been a while since i updated this, but i added the Fuel Injection Upgrade last weekend. Went on a mild 4 wheelin excursion thru Four Peaks, and coming back home on I-87 the Burb started bucking real bad climbing a steep hill on the highway in O.D. Buckin was associated with a Check Engine light that eventually started flashing. Dropped it into 3rd gear and the flashing and bucking stopped.
When i checked the codes it came up P0300 Random Misfire. So since ive had previous problems with the Poppet valves on road trips. Decided to take the Plunge.

Noticed a smoother idle, and better Acceleration. Havent tried it on the hills yet, but the wife wants to go to Flagstaff and play in the Snow so that will be the hill test.

My next upgrade will be a 14BSF. Have been researching the swap, and will be hitting the Junkyards soon.
 
I got the 14bsf thing going on "someday" too . Actually using the six lugger out of my 93 pickup I started stripping , same gearing and open so I can add a lockrite later .

Going to need to add the swaybar brackets as some pickups don't have them .
 
Went up to Flagg and the Suburban performed perfect. No miss or bucking going up the hills. Actually noticed more power climbing and more brake horespower coming down. If u haven't done the injector upgrade on these Vortec motors I highly recommend u do. The next big test will be when we take our Annual Camping Trip in Heber and see how it pulls my trailer up them hills.
 
What is the fuel injector upgrade you mention? We just got a 99 burn and I'm trying to get a little more mileage from it.
 

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