:::RHMT::: Real Home Made Turbo

General Category => Hybrid/Tech => Topic started by: jdmhatchracer94 on February 21, 2012, 03:38:43 AM

Title: tb how big is to big?
Post by: jdmhatchracer94 on February 21, 2012, 03:38:43 AM
just picked up a blox 76mm tb for dirt but wondering if it is to large for me setup? Will it hurt performance at all or not?
Title: Re: tb how big is to big?
Post by: PhilStubbs on February 21, 2012, 07:45:19 AM
My understanding of it is that with any oem Honda manifold, it will limit your tb size before your tb is too big. I have tuned an assload of cars, but none of them had bigger tb's than an s2k tb. So, I could be wrong.
Title: Re: tb how big is to big?
Post by: 92CXyD on February 21, 2012, 08:33:29 AM
just picked up a blox 76mm tb for dirt but wondering if it is to large for me setup? Will it hurt performance at all or not?

It be golden, if you get a spacer that smooths out the transition from bore size of backside of tb to the largest bore size your b-series mani. can go w/o messing up the IAC circuit.

BTW is that 76mm at the inlet side or the mani side?

I use to see 80mm Ford TBs on the GSR manifolds for drag racing in the late '90s, so I see no problem.

It would different if it was carb(s), size of these can very critical.  :noel: 
Title: Re: tb how big is to big?
Post by: JACER63 on February 21, 2012, 06:44:30 PM
more boost=more air... your golden.. it will be solid
Title: Re: tb how big is to big?
Post by: jdmhatchracer94 on February 22, 2012, 02:58:47 AM
golden eagle manifold so I;m good there. Saw something about horrible part throttle is hard to tune with a large tb. Dunno if it's true as I am no tuner but we will see. I guess.
Title: Re: tb how big is to big?
Post by: HiProfile on February 22, 2012, 03:37:08 AM
The only reason it would be hard is because it will be like a light switch. 10% throttle with 76mm will feel like 3/4 throttle. Even 60mm TB's feel like that IMO, and I really hate it.

If you want it to be more linear, you need a non-linear pulley for the cable. It should be offset so it puts the cable far away at idle, and close at WOT. This gives the first 50% of pedal less than 50% of throttle angle, and the last 50% of pedal more than 50% of angle. I'll be doing this to a GSR TB eventually, since the pulley/cable are at the perfect angle to do so.