throttle body sizes?
Thread Starter
On The Tree
Joined: May 2012
Posts: 133
Likes: 1
throttle body sizes? ok so we built a twin 70mm turbo 6l - bone stock engine at the moment
has hp tune in it and runs 15 psi boost and water meth
hp seems to be down a bit from what we read on here for similar setups
we are hitting around 520hp to the wheels at 5200 rpm - cant keep it locked down from there and just spin the tires.
anyway - out on the road - anything after about 5500 rpm, boost starts to drop from 15psi down to 12 psi and sits there rock steady - anything under 5500 rpm and it sits rock steady at 15psi
we are wondering if we are running out of air - meaning the stock throttle body may be too small?
we are running a walbro 340 pump and 80# seimens deka injectors so we dont think it is a fuel issue
it is drive by wire, and with the dollar the way it is up here in Canada a new 101 mm drive by wire throttle body is about a grand landed here - so we dont want to be throwin money at it if thats not the issue
any thoughts or suggestions on what to check, or test?
what are you higher hp guys runnin for a throttle body size?
thanks
has hp tune in it and runs 15 psi boost and water meth
hp seems to be down a bit from what we read on here for similar setups
we are hitting around 520hp to the wheels at 5200 rpm - cant keep it locked down from there and just spin the tires.
anyway - out on the road - anything after about 5500 rpm, boost starts to drop from 15psi down to 12 psi and sits there rock steady - anything under 5500 rpm and it sits rock steady at 15psi
we are wondering if we are running out of air - meaning the stock throttle body may be too small?
we are running a walbro 340 pump and 80# seimens deka injectors so we dont think it is a fuel issue
it is drive by wire, and with the dollar the way it is up here in Canada a new 101 mm drive by wire throttle body is about a grand landed here - so we dont want to be throwin money at it if thats not the issue
any thoughts or suggestions on what to check, or test?
what are you higher hp guys runnin for a throttle body size?
thanks
Trending Topics
You probably have massive tuning issues. Log some data and post it up. That being said, an intake side boost leak could also cause similar problems. If your engine is truly bone stock internally, you may also have valvespring issues at 15#'s of boost. With twin 70's your boost drop is NOT because of TB size.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
I doubt it’s the TB. What’s your fuel flow look like? If the fuel flow is there and everything else seems fine engine wise (valve springs etc), look at the converter/trans for your slip % VS gearing/tire size. I bet it’s way off.
I’d guess your converter isn’t coupling well below 5200RPM, then as soon as the converter starts to couple it blows the tires off.
The boost dropping sounds like a WG spring VS back pressure issue. As soon as boost builds so does back pressure and it’s opening the WG. Put a stiffer WG spring in it (or shim the one you have) and see if that aspect changes.
Would be ideal to setup HP to progressively add boost is some way….
Good luck!
I’d guess your converter isn’t coupling well below 5200RPM, then as soon as the converter starts to couple it blows the tires off.
The boost dropping sounds like a WG spring VS back pressure issue. As soon as boost builds so does back pressure and it’s opening the WG. Put a stiffer WG spring in it (or shim the one you have) and see if that aspect changes.
Would be ideal to setup HP to progressively add boost is some way….
Good luck!
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
ok so we built a twin 70mm turbo 6l - bone stock engine at the moment
has hp tune in it and runs 15 psi boost and water meth
hp seems to be down a bit from what we read on here for similar setups
we are hitting around 520hp to the wheels at 5200 rpm - cant keep it locked down from there and just spin the tires.
anyway - out on the road - anything after about 5500 rpm, boost starts to drop from 15psi down to 12 psi and sits there rock steady - anything under 5500 rpm and it sits rock steady at 15psi
we are wondering if we are running out of air - meaning the stock throttle body may be too small?
we are running a walbro 340 pump and 80# seimens deka injectors so we dont think it is a fuel issue
it is drive by wire, and with the dollar the way it is up here in Canada a new 101 mm drive by wire throttle body is about a grand landed here - so we dont want to be throwin money at it if thats not the issue
any thoughts or suggestions on what to check, or test?
what are you higher hp guys runnin for a throttle body size?
thanks
has hp tune in it and runs 15 psi boost and water meth
hp seems to be down a bit from what we read on here for similar setups
we are hitting around 520hp to the wheels at 5200 rpm - cant keep it locked down from there and just spin the tires.
anyway - out on the road - anything after about 5500 rpm, boost starts to drop from 15psi down to 12 psi and sits there rock steady - anything under 5500 rpm and it sits rock steady at 15psi
we are wondering if we are running out of air - meaning the stock throttle body may be too small?
we are running a walbro 340 pump and 80# seimens deka injectors so we dont think it is a fuel issue
it is drive by wire, and with the dollar the way it is up here in Canada a new 101 mm drive by wire throttle body is about a grand landed here - so we dont want to be throwin money at it if thats not the issue
any thoughts or suggestions on what to check, or test?
what are you higher hp guys runnin for a throttle body size?
thanks
Stock TB will cope with about 4x the power you're making...and then some...and then maybe a bit more
So basically you need a better form of boost control and some better tuning.
