An FC with a N/A 20B or a TII slightly modded?

Would it be more expensive to convert a N/A to turbo using the TII driveline or swapping in a 20B?

 

I'd rather have the 20B. Yes, it would be considerably more expensive and difficult to install the 20B.

 

Why would anyone install an N/A 20B? You'd have to want to change out the rotors to higher compression, meaning a rebuild is required, and the engine already comes with a turbo system attached!!

Regardless, N/A or Turbo'd, a 20B is DEFINITELY more expensive. If you can't do a N/A to Turbo swap for less than $15K, you've done sometyhing wrong.

 

Oh, yes. I've seen a rx7 run an 8 quater mile. with a TT 20b

 

I suppose the question should have been:

Would you choose a normally aspirated engine over a pressurized one? similar power outputs, with the N/A being the more expensive option.

 

That's a good question, but I would have to say the 20B....serious room for improvement.

 

OK, I've been through most of this already. I didn't always make the right choices, but I have learned from my mistakes as well as my success. Here's my opinion based on my experiences:

1) Start with a TII. If you have an NA, then sell it and buy a TII. If your NA just has too many mods to part with, then buy a TII with a blown engine and swap out ALL the suspension, brake, and driveline parts, along with a rebuilt or otherwise decent TII engine. The "NA to TII" conversion is not very smart 90% of the time, but there are exceptions.
2) Don't bother with a FCD, intake or exhaust yet; just go to the next step.
3) Once you have about $2K saved up, add an aftermarket EMS, high-flow fuel pump (Aeromotive or SX "1000hp models"), SX fuel pressure regulator, high-flow fuel filter, upgraded fuel lines, and aftermarket boost gauge. Now you don't need that $100 FCD, and you can safely add whatever intake and exhaust components you like as long as you watch your boost gauge and air-fuel ratio on the EMS.
4) As time and money permits, slowly upgrade your car. Add a huge front-mount intercooler, competition radiator, and the best electric fan(s) you can find. When the clutch wears out, replace it with a 2-disk clutch. Note that the current aftermarket front swaybars will not work with a 20B, so either pass on this upgrade or make a custom bar. Hopefully a production 20B-friendly swaybar will be offered to the public one day.
5) Once you have completed everything in #3 & 4, and you have about $6K saved up, then install a STOCK-turbo 20B-REW.
6) Once everything is running well with the stock-turbo 20B-REW, then you can spend the $10-15K or so converting to a big single turbo or a fire-breathing NA. I suggest the single turbo unless you want to race in a category (GT for example) in which turbos are not allowed.

Bottom line: Go for the TII, and then convert to a 20B at a later time if you like.

 

Agreed, except that the stock 9.0:1 20B rotors are just fine for use in NA form. However, if you want to get a lot of power out of an NA 20B, you will need to run it at higher rpms, which means lightened rotors, porting, dry sump, etc., which would require a rebuild.

The price depends on how you do them, but yes, the NA conversion would be more expensive given the same hp levels. While their outputs may be similar at lower levels, their max outputs are NOT similar. A maxed-out 20B NA is around 475hp (75hp less than Pettit's street-legal stock-turbo street port 20B LOL), while a maxed-out turbocharged 20B can make over 1000hp.