slicksierra

Feel some type of way
Mar 8, 2012
5,464
174
63
31
Central Jersey
Word yeah I looked over that thread. Not for me since I don't have a welder. I'd only ever do it if it could do it all on the cheap. And after other mods just trying to sort it all out. I think it's been proven though that a larger TB is useless unless big cube or FI


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Fiesty

Active Member
Jul 28, 2013
2,698
13
38
30
Kansas City, MO
Word yeah I looked over that thread. Not for me since I don't have a welder. I'd only ever do it if it could do it all on the cheap. And after other mods just trying to sort it all out. I think it's been proven though that a larger TB is useless unless big cube or FI
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Ask @Low01Silverad0 and he will tell you otherwise.

I don't have a welder either. Paid a friend of a friend $20 to weld it.
 

Samuel6731

Cant Get Right
Mar 11, 2012
674
1
18
New Roads La.
They way I did was easier and cheaper. I used my stock 99-02 truck fuel rails and injectors. I cut up the fuel rail crossover and welded an AN fitting on each side, then got a braided fuel line with fittings to use as a new crossover. You'll also need spacers to use ur stock fuel rails. I'd personally run a 92mm aftermarket throttle body (FAST, Nick Williams, or Edelbrock) since there's more power left on the table, instead of running an adapter. With this method you don't have to fuck with corvette filters for the return fuel system.
No offense but I prob wouldn't bother doing a TBSS intake on a stock 4.8.

Here's the write up I used though. 99-02 ONLY TBSS Intake on 99-02 - PerformanceTrucks.net Forums



Buddy of mine did the fuel lines the same way as that. came out nice

In all honestly for a 4.8 or 5.3 i dont think this swap is necessary unless your spin 6400 up. the stock manifolds flow well enough
 

Cleanoh4

Well-Known Member
Aug 27, 2013
4,346
184
63
40
NJ
So having now down this swap, there are a few things I learned/figured out along the way that are missing from both the write up and the Bgerald one.

1.) If you get the right year NNBS (07-08) or actual Trailblazer SS (06-08) I/M your stock NBS Map sensor will fit just fine, with absolutely no height clearance issues ( no bending, drilling,wiring down) and with out breaking any tabs, all while allowing you to use your factory plug. The part numbers are identical.



2.) If you have mechanical fans, and run the stock NBS TB youre gonna be real close to the shroud after adding the spacer required. (My next plan is efans)

3.) Fuck the coolant line running through the TB, they are a pain in the ass both to take off and put back on, so unless you live in a really cold place, bypass it on install

4.) Injectors, EVAP, fuel lines and rails all fit fine. My NNBS intake came with the EVAP solenoid and line back to the rear of the motor, so i took my old one off and swapped that one on.

5.) Might as well do your knock sensors and harness if youre going to be in there anyway

6.) Same note, might as well add a catch can, because, well you do half the work anyway.
 

Bassmaster

Media Mod
Mar 8, 2012
10,302
147
63
South Jersey
You have a real tbss intake, 90mm(?) , vs the nnbs intake which is 87mm(?). As far I know that's the only difference, but jsyk

Nice additional tips!
 

Jake747

Well-Known Member
May 13, 2015
1,006
41
48
44
Seattle
I deleted my EVAP so if you have HPTuners it's really easy to do. Just to clean the area up and would be one less thing to worry about swapping over.
 

Cleanoh4

Well-Known Member
Aug 27, 2013
4,346
184
63
40
NJ
I deleted my EVAP so if you have HPTuners it's really easy to do. Just to clean the area up and would be one less thing to worry about swapping over.

It literally swapped right over and was really easy to do. I didnt have to buy anything extra or do anything different to keep it, so I did.

My only pseudo regret is not swapping the TB, but I can always do that down the line for minimal cost and effort.
 

Low01silveradO

New Member
Nov 27, 2012
498
1
0
Just to add a bit of info in here. The stock rails setup with braided crossover is the way to go. If I did it again that's what id do no doubt. I'm now in the process of cutting my stock rails and using those and ditching the nnbs rails and vette filter setup

Also, don't use injector plug adapters. Mine worked great for 3 years, now they are causing problems. I'm changing the connectors on the harness to ev6

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Cleanoh4

Well-Known Member
Aug 27, 2013
4,346
184
63
40
NJ
Just to add a bit of info in here. The stock rails setup with braided crossover is the way to go. If I did it again that's what id do no doubt. I'm now in the process of cutting my stock rails and using those and ditching the nnbs rails and vette filter setup

Also, don't use injector plug adapters. Mine worked great for 3 years, now they are causing problems. I'm changing the connectors on the harness to ev6

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What was your problem in using the TB/NNBS rails? I used it and have had zero issues thus far. Also kept my stock NBS injectors and with my configuration and according to BBP they arent close to being maxed out.
 

Low01silveradO

New Member
Nov 27, 2012
498
1
0
What was your problem in using the TB/NNBS rails? I used it and have had zero issues thus far. Also kept my stock NBS injectors and with my configuration and according to BBP they arent close to being maxed out.
My stock injectors can't be used in my setup. I'm pushing the 28lb nnbs injectors to the limit as it is

The nnbs rails are fine but I set it up where the vette filter was on the rail, looked real clean but it pushes the fuel lines up against the firewall. And then if u make a loop out of braided hose and put the vette filter next to the rail it looks janky as fuck. The stock rails setup is just all around simpler, less crap, better setup. Also keeps u from having 2 fuel filters, which isn't necessary.

However it worked for 32,000 miles. But I think the fuel lines being pushed against the firewall contributes to the sometimes random hard starting. But always ran great

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Cleanoh4

Well-Known Member
Aug 27, 2013
4,346
184
63
40
NJ
My stock injectors can't be used in my setup. I'm pushing the 28lb nnbs injectors to the limit as it is

The nnbs rails are fine but I set it up where the vette filter was on the rail, looked real clean but it pushes the fuel lines up against the firewall. And then if u make a loop out of braided hose and put the vette filter next to the rail it looks janky as fuck. The stock rails setup is just all around simpler, less crap, better setup. Also keeps u from having 2 fuel filters, which isn't necessary.

However it worked for 32,000 miles. But I think the fuel lines being pushed against the firewall contributes to the sometimes random hard starting. But always ran great

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So your issue was in that you weren't a returnless system. I can see where that would make sense on the 99-02.
 

Khaos

Bed Dent Club Founder
Mar 24, 2012
20,378
1,566
113
Albany, NY
What was your problem in using the TB/NNBS rails? I used it and have had zero issues thus far. Also kept my stock NBS injectors and with my configuration and according to BBP they arent close to being maxed out.
He has a return style system on his 01, you have returnless. Little more work to be done on a return system.
 

Low01silveradO

New Member
Nov 27, 2012
498
1
0
He has a return style system on his 01, you have returnless. Little more work to be done on a return system.
What he said
So your issue was in that you weren't a returnless system. I can see where that would make sense on the 99-02.
99-02 is return style. And stock rails is the way to go on 99-02. On 03+ u can use the nnbs rails as is with no extra parts. So clearly that's the way to go for 03+

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