| How to Siamese TPI Base |
| Background The stock TPI intake, base, runners, plenum are good at building low RPM torque but suffer from inability to supply sufficient air at upper RPM. The goal is to retain the stock TPI look while enhancing upper RPM torque, and so HP, without loss to mid-range and low end torque. The purpose of this page is to provide the best information sources at my disposal on this topic. |
| Possible Solutions 1) Big Mouth base & large-tube runners: These have the same runner length as TPI with larger diameter tubes. It builds better mid-range with no low RPM torque loss but is rather expensive. 2) Siamesed runners (and plenum): This builds better mid-range and upper RPM torque but lose some low end torque and is moderately expensive. 3) Siamesed base: This new concept has been shown to build much better upper RPM torque with supposedly no low end loss and has virtually no expense other than 8-10hrs of labor. |
| Description The Siamesed Base is an ingenious concept that I believe is first performed back in February of this year by MadMax of Third-Gen fame. The basic concept is to partly grind out the wall between two adjacent runners in the stock intake base. There are several vesrions as to how far into the base to grind, whether to grind the lower runners and whether to grind into the upper runners and plenum. To date several people have done this type of mod with great success. 1) Madmax on the Third-Gen F-body forum at Original Article on Siamesed Base 2) Another Third-Gen F-body forum link at Second Article on Siamesed Base 3) Follow the progress of 88L98 on the Corvette Forum Tech/Performance board. |
| Future Project My plan was to add the Big Mouth base and large tube runners to my L98. However, now I intend to try this mod first; if it works it will be the best of all worlds and low cost. If it doesn't work as advertised I can still fall back on the original plan with not much $$ loss. |