70mm thottle body

[gradon]

The 60mm bored out renix tb definitely helps the renix 4.0 breathe better--no brainer for $100. It helps close the renix-ho horsepower difference--the HO's 7120 shorter ports with matching intake manifold, bigger injectors, and no egr also are part of the difference. I'm not convinced the ho/obd2 electronics are better than renix yet. I use a 62mm w/half shaft tb on my medium 4.6. Someday I'd like to try a bigger one(my 3.0l m3 that can rev to 7k has a 68mm tb that Jeff bored).

 

[DieselSJ]

Assume 80%to 85% VE.
====================
True: But Max VE do not happen at max RPM as some may think. Max VE happens at ABOUT max torque or real close to it. That's why torque start to fall of above that RPM because VE starts to drop even with RPM going up.
If you want to know how big a TB you will need at SAY 6k RPM or so drop that VE to 55~65%. That's with a catback system and a funny looking cone air cleaner.
Now with a bad ass cam, some real head work, headers, OPEN headers that is and/or some kind of blower. Real VE numbers can change.
A 70 MM TB is good for bragging rights and little else. But go for it. Over size TB are a lot easier to live with on a DD. Then over carb was.

The VE on our racer is 85-90 in the 5k-6K rpm range.
At torque peak is is 96.

 

[Dr. Dyno]

I use a 62mm w/half shaft tb on my medium 4.6. Someday I'd like to try a bigger one(my 3.0l m3 that can rev to 7k has a 68mm tb that Jeff bored).

Don't bother. Unless you rev your stroker well beyond 5000rpm (pretty unlikely), the 62mm TB flows more than enough air.

 

[badron]

The VE on our racer is 85-90 in the 5k-6K rpm range.
===========================================
DAM 96% max with 85 at 6k from an old stump puller, Sounds like a sweet flat torque curve.
What type of cam are you running? In what type of racing? Got any numbers above 6K or is that the lifters limit.

 

[DieselSJ]

The VE on our racer is 85-90 in the 5k-6K rpm range.
===========================================
DAM 96% max with 85 at 6k from an old stump puller, Sounds like a sweet flat torque curve.
What type of cam are you running? In what type of racing? Got any numbers above 6K or is that the lifters limit.

Very flat. Pulls hard everywhere in the RPM range.

Cam is something custom that we came up with in working with Clay Smith (they do all the cams for Hesco). Desert racing - Jeepspeed class. 6K is where we have the rev limit set. Power would drop dramatically after that anyway with this cam.