Turbo on a stock fi b3?

[JoelRowntree]

Just curious how hardy the bottom end of the 1.3 is... i am about to turbo my stock festiva on 5-8 lbs of boost and im curious how it will hold up. My festiva is an 89 converted to fuel injection. Looking to boost the power a little bit. Any information would be great. Thanks

[william]

Never done it but I hear they hold together if you keep it under 10 psi. Someone els will chime in here I'm sure.

[eurotiva]

I ran 10lbs on my b3. Funnest setup ever. The clutch is gonna be the limiting factor

[Sleeper]

For the most part you can bolt on all the bits from a b6t to the b3..... not sure about the oil lines to the turbo tho....

[TominMO]

Just don't launch it and the tranny and clutch should hold up fine. Motor is no problem, they can take it.

[JoelRowntree]

Hey, thank you all for the input, i appreciate it very much. I have two engines and two transmissions and a full turbo kit with a 25r from a single cam civic i had awhile ago so im gonna give it a whirl! I just bought the steel manifold to get the head flange so i can weld up a manifold. Ill update when i get the turbo setup fabbed up. Anyone got a pic of the block with the head off? Is it a closed deck or sleeved?

[Advancedynamix]

It's an iron block, with traditional bores. The b3 is the weakest of the Mazda B series engines. Most of the guys who have turbocharged them have blown them up within a year. The DOHC Mazda B series engines have much stronger components (blocks, cranks, rods and pistons are all much stronger). A gt25r will be excessive for a stock B3. Slap that turbo on a b6d and you'll be miles ahead of the B3 performance without much investment. The clutch will be your weakest link with over 120hp. Spec makes one that may hold more (depending on what day your spec clutch is made) but they take the fun out of driving because it shutters a lot. I can't stand my spec stage 2.

[JoelRowntree]

Hey, thanks for the input! I have built numerous turbo civics from the ground up and just recently sold my civic drag car which was running in the 11's (dyno'd 552 whp) so i could put a downpayment on the house i just bought... just to give you an idea of my experience with turbo engines. I totally understand that the turbo isnt right for this size engine and probably wont spool til 5k and possibly overboost and do more damage than good..it is pretty irresponsible.... Im going to see if i can find a smaller turbo for cheap and ill go from there.

[Advancedynamix]

Try a gt1752 from a Saab 9-3. Cheap as dirt, good turbo and a realy nice internal wastegate to keep things under control. If you stay modest with the boost, avoid detonation at all cost and keep in mind that this engine was never intended for boost, you'll probably get some mileage out of it. Most people get greedy and find new ways to ventilate the block, but that's not just a b3 problem, lol.

[Aaronbrook37]

It's an iron block, with traditional bores. The b3 is the weakest of the Mazda B series engines. Most of the guys who have turbocharged them have blown them up within a year. The DOHC Mazda B series engines have much stronger components (blocks, cranks, rods and pistons are all much stronger). A gt25r will be excessive for a stock B3. Slap that turbo on a b6d and you'll be miles ahead of the B3 performance without much investment. The clutch will be your weakest link with over 120hp. Spec makes one that may hold more (depending on what day your spec clutch is made) but they take the fun out of driving because it shutters a lot. I can't stand my spec stage 2.

Charlie, what are your thoughts for those of us stuck with a B6 SOHC in terms of forced induction? From what I know, my 323's B6 (1986 model year) has de facto identical manifolds and a top half of the motor to the Festiva B3 based on my comparisons of the gasket set. I suppose the same rule of thumb holds true that the second camshaft or extra displacement would be more worthwhile than trying to push more air than is reasonable through eight valves. I would gather that 8-10psi on the 1.6L SOHC would be nothing to scoff at, though. Tempting to try and track down another B6T, particularly since there are a large number of Capri XR2's just on the other side of the border for <$1000 each from time to time.

[JoelRowntree]

To advanceddynamics_ just dug my turbo out of the box and to my surprise its a td05 off an evo.... still not very good for this engine.. the turbine is a .70 im not sure where i got the 25r from...

[Advancedynamix]

Charlie, what are your thoughts for those of us stuck with a B6 SOHC in terms of forced induction? From what I know, my 323's B6 (1986 model year) has de facto identical manifolds and a top half of the motor to the Festiva B3 based on my comparisons of the gasket set. I suppose the same rule of thumb holds true that the second camshaft or extra displacement would be more worthwhile than trying to push more air than is reasonable through eight valves. I would gather that 8-10psi on the 1.6L SOHC would be nothing to scoff at, though. Tempting to try and track down another B6T, particularly since there are a large number of Capri XR2's just on the other side of the border for <$1000 each from time to time.

The SOHC engines are weaker in virtually every aspect. The cranks are single throw counterbalanced, which is a problem when severe loads are placed on the engine (inline 4 cylinder engines are much more prone to harmonic related failures than most other configurations, therefore the crank design and weight is critical). The piston pin design, rod design and piston designs are all much less durable for aggressive driving. The oil pump on the SOHC engines is smaller. The SOHC engines don't have oil squirters under the pistons. Contrary to some tuners advice, oil squirters are very beneficial to turbocharged engines. They help reduce hot spots on the pistons, they help cool and lubricate the pistons and small end rod bearings. Oil squirters also supply a constant film of oil under the pistons which helps dampen harmonics that can lead to cracks in the piston skirts. I prefer to turbocharge engines with oil squirters under the pistons.

You don't need to find a b6t. The Miata 1.6 is very close to the same engine. An automatic Miata 1.6 is a really good start.
Throwing a turbo on anything can be a good time, but it's better to start off with a stronger engine. The SOHC b series engines were not created equal to the race bred dohc b6 or Bp engines.

[Advancedynamix]

To advanceddynamics_ just dug my turbo out of the box and to my surprise its a td05 off an evo.... still not very good for this engine.. the turbine is a .70 im not sure where i got the 25r from...

Yeah, and it's a goofy flange. If you don't like it, you'd have to cut it off to fit most anything else or pay a lot for a td05 hybrid.
The gt1752 is a t2 flange, so you can swap it out for a gt2554 if you want more.
The China version of the 1752 is available for less than 150 bucks shipped on eBay. It'll probably outlast the b3.

[JoelRowntree]

Ive never used an fmu before... anybody know what ratio to use? 6:1?

[eurotiva]

Ive never used an fmu before... anybody know what ratio to use? 6:1?

I used a 12:1