TBI or TPI
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
The TPI intake manifold design is superior, with more runner length and volume. TPI also allows for 8 injectors instead of 2, allowing better fuel atomization and distribution. It was worth 25 HP over the 205 '84. 
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
it was worth 25 HP because the general sabotaged the TBI system, use a similar runner sized TBI system and it'll blow away the stock TPI..honestly. The TPI has long runners, like the CFI and it was also designed for the 305 like the CFI but it certainly does not have this:
without welding this is all you can do:
There's your 25HP..right there.
You're right, fuel distribution is better but it's still batch fire (a whole bank fires at the same time) so it's not much different from the 2 TBs firing in alternate order (or together..depending on enrichment mode) The major advantage is the dry plenum so for the same volume you have more air into the engine because there's no fuel to take up some of the space. IMO the tBI sounds much sweeter, like a carb because of the unequal distribution..it sounds nasty and not like a swewing machine like the batch fire multipoint and sefi systems do.
without welding this is all you can do:
There's your 25HP..right there.
You're right, fuel distribution is better but it's still batch fire (a whole bank fires at the same time) so it's not much different from the 2 TBs firing in alternate order (or together..depending on enrichment mode) The major advantage is the dry plenum so for the same volume you have more air into the engine because there's no fuel to take up some of the space. IMO the tBI sounds much sweeter, like a carb because of the unequal distribution..it sounds nasty and not like a swewing machine like the batch fire multipoint and sefi systems do.
