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Welcome to the 3500HD.com forum created October 2009

Author Topic: TBI tuning option!  (Read 661 times)


MrC.

  • One Ton Driver
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  • Posts: 50
Re: TBI tuning option!
« Reply #1 on: January 04, 2018, 01:56:25 PM »
Hey Ed.

I'm glad you posted this.

I have been reading we (3500hd's) have a higher pressure regulator factory. I have read it is 30 psi as opposed to the 13-15 psi of a half ton truck. I have also read we have small stock injectors 42#. I have been thinking about replacing my stock injectors with 55-60# units. and adding a chip (maybe a custom one) along with free flowing exhaust (no cats).
Would you see a power gain in this setup of am I missing something?

I had a 95 tbi 1/2 ton w/ 305 back in 96, I changed out to larger Holley injectors, and raised the stock pressure to 20 psi, along with a chip and underdrive pulleys and exhaust, it was noticeable. and smoked stock 350's of the day. I was hoping to repeat those results with my 3500hd.

Any advice?

Thanks,
MrC.

ED-NY

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  • 3500HD Hero
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  • Age: 67
  • Location: Champlain, NY
Re: TBI tuning option!
« Reply #2 on: January 04, 2018, 06:14:59 PM »
Don't remember which engine you have but fuel alone won't make a huge difference. As you know, heads, cam and exhaust need to be included in a performance upgrade.  I have had luck un-soldering the proms in 1227747 ECM and soldering in a zif socket so we could use a flashable prom.

What I did with my current 3500HD is install a TPI setup and wired in a TPI ecm to run it. Did not put it on the road yet, it's done but I don't want to drive it in the Winter.  The truck is parked outside and has been sitting for a couple of months....this AM it fired right up. I'll know in Spring how it works, the TPI engines are noted for low end torque.

someotherguy

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Re: TBI tuning option!
« Reply #3 on: January 05, 2018, 09:01:26 AM »
I have been reading we (3500hd's) have a higher pressure regulator factory. I have read it is 30 psi as opposed to the 13-15 psi of a half ton truck. I have also read we have small stock injectors 42#
It's not a 3500HD thing.  The 1994-1995 7.4 engine has a higher pressure pump and different injectors than the earlier years, even in the 3500 and 2500 trucks.

Richard
06 Silverado ISS / 06 Silverado SS / 06 300C SRT8

MrC.

  • One Ton Driver
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  • Posts: 50
Re: TBI tuning option!
« Reply #4 on: January 05, 2018, 03:14:46 PM »
You are right Someotherguy, I did read that only 94-95 3500HD's had the high pressure pump. Thanks for stating that.

I have a 1994 3500hd. I have not checked the pressure, but from what I have read it should be 30psi with 42# injectors.
That said, would there be any gains if I switched to a 50-60# injectors and removed the cat and opened up the exhaust?

Thanks
MrC.

 


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