In speaking with a former FD3 owner (who is lamenting being one), he informed me of a simple mod that according to him gained noticeable hp (he was claiming 15 hp, but after thinking about it, extremely doubtful). It involves bypassing the "warm-up heater tubes" leading to the intake plenum. Apparently they're there to aid in warm-up by circulating rapidly heating coolant through the plenum body (if you look at cutaway drawings of the intake plenum, there are multiple passages inside the plenum body for the coolant feed). However, I notice that my FD has no problems warming up, even on cold mornings, with moderate mods (DP, CB, modded airbox, SMIC, etc.). Thus, I find not much reason to use the intake plenum as a heat exchanger, when you want the intake charge as cool as possible. Kevin Wyum said it's a no-brainer mod (both for its reliability aspect and apparent ease), and I've searched for any threads relating to this, but haven't found any. Has anyone else performed this simple mod, and did it make any noticeable difference? I'll probably end up doing anyway for the aforementioned reasons given by Kevin, but I was just curious.

Kento

 

I believe there is a step-by-step on Rob Robinette's site/old site. http://www.rx7turboturbo.com. Keep us posted on your findings if you continue with the bypass. Good luck.

Kyle

 

I just tried going there myself and it looks like that site is down for some reason. Another great site you might try is http://www.scuderiaciriani.com/rx7/index.html.

Kyle

 

You can get to Robinettes site with www.rx7.org/Robinette/

I would love to believe that this is an hp mod but there is not a chance this is going to make 15 hp. Maybe .15, but, what the heck?

 

Aha! Found it on both of the sites, listed as "Throttle Body Coolant Hose Removal". Thanx for the help, guys. Guess I need to do more extensive searches before posting questions....

Kento

 

No problemo, that's a "mirror" address and until just a few days ago I had no idea how to get there either!

 

If you do this the way Garfinkle does you get rid of 3 hoses and 1 steel tube. That is 6 joints that could leak. He pulles the metal nipple from the water pump housing and the one from the rear housing, and puts in threaded pipe plugs, he puts rubber plugs on the throttle body nipples to keep out dirt. this way you can pipe threaded nipples to replace the system if you need, no one has gone back as of yet. Cold starts ar no problem .

 

I did this caused I hated messing with the coolant line at the bottom of the TB. Problem is it will mess with your fast cam idle and you'll be idling high unless you crank the adjusting screw all the way in.

There is no hp increase unless you put a Honda sticker on the windshield.

 

Just make sure you caveat that statement of 15hp gain by saying Kevin Wyum is not the person that said that, since my my name is the only one in that post : ).

Kevin T. Wyum

 

Since this thread was brought up from the dead, I will say that Kevin T. Wyum was not the person who was claiming 15 hp from the coolant/TB bypass mod.

The only thing this mod does IMO is simplify the coolant system somewhat, by getting rid of another coolant path.

 

you also don't have 190*F fluids creating a heat exchanger in your intake system....seems pretty common sense to me.

i've been running this way for longer than i can remember....

 

Any have some good pictures?