| Author | Message | ||
     Edward Mah (Emah) New Member Username: Emah Post Number: 33 Registered: 11-2002 |
Has anyone rebored the heads and exhaust to a larger diameter and polished them? I was at my friends LR shop and he was telling me how that would increase the horse power on my 95 DI. He also mentioned the increased gas consumption. Just want to know if anyone has done it and whether it's worth it just for the added power. Ed | ||
| Kyle Van Tassel (Kyle) Moderator Username: Kyle Post Number: 113 Registered: 11-2002 |
Also loss of torque... Kyle "Blow me" | ||
| Edward Mah (Emah) New Member Username: Emah Post Number: 35 Registered: 11-2002 |
Why is there loss of torque? Ed | ||
| Greg Hirst (Gregh) Member Username: Gregh Post Number: 106 Registered: 10-2002 |
Are you talking about ExtrudeHone process or just port and polish? Either way you'd probably lose port velocity from stock and ruin some perfectly good heads and also loss of torque. | ||
| Edward Mah (Emah) New Member Username: Emah Post Number: 36 Registered: 11-2002 |
I'm not sure to be honest with you. I was shown the removed heads and told that if the heads were bored out bigger and polished that it would yield increase the horse power but that was all he told me. Loss of torque was never mentioned. I don't understand why there would be a loss of torque...can you expand on that? Is there port velocity loss because there is a reduced venturi effect? Thanks, Ed | ||
| Ron L (Ronl) New Member Username: Ronl Post Number: 10 Registered: 11-2002 |
Can of worms! Never mind the loss of torque, if you are not utilizing the increased port velocity with the proper cam you will not see much of a gain in HP. More air means more fuel. More fuel means larger injector or increased fuel delivery via regulator and or fuel pump, recalibrated air sensor, the list goes on and on. | ||
| Edward Mah (Emah) New Member Username: Emah Post Number: 39 Registered: 11-2002 |
That makes sense. Good to know...Thanks Ron! E | ||
| Kyle Van Tassel (Kyle) Moderator Username: Kyle Post Number: 115 Registered: 11-2002 |
Right Ron , and what he will see (feel) is an imediate loss of torque... Kyle "Blow me" | ||
| Ron L (Ronl) New Member Username: Ronl Post Number: 11 Registered: 11-2002 |
No doubt about it. Thats worth much more in something that weighs a ton. Simple theory, if you cant get it going (torque) then there is no reason to keep it going (hp). | ||
| Greg Hirst (Gregh) Member Username: Gregh Post Number: 108 Registered: 10-2002 |
Can of worms is right-there's a lot of factors here (fuel delivery capacity, cam lift and duration, exhaust size and design, intake flow, even valve size etc.) However, even if head work was done by someone who knew their stuff with a flow bench (and all other factors corrected to take advantage of increased flow),IMHO it adds up to increased HP at higher RPM's. I don't know of any trail rigs that are looking for HP at 5K+ RPM. What I'm looking for myself is simply cheap and reliable torque at lower RPM's where I can use it. To me that means increased displacement. |
