Bypass Valve Mod (Jekkyl & Hyde)

Jeff sometime ago you answered one of my post regarding BOV etc..,your advise was the to keep the factory bypass valve since you will loose performance by puting in a conventional BOV, you also said the closest thing to the factory bypass valve was the HKS SSQ BOV, as i said before all i really wanted was the cool BOV noises, you also mentioned that you did a modification to the factory unit by puting in a small filter so you can get those sounds without sacrificing performance.

I had a look at one of your post's which had your engine bay pics, very nice! im trying to do the same, how hard is this mod to do? can you give me some hints and possibly a list of what i need so i can replicate exactly what you did.

Can i also pick your brain on a couple of things if you dont mind :), i have a stock 95 gen III MR2 GT, only mods that ive done to it so far is an HKS super dragger twin exhaust system and an HKS panel filter using the factory airbox, this is a jap import so i would pressume that being a gen III it would have 245hp in stock form. to cut a long story short im starting to look for more power next mods is a pod filter and a dump pipe.

now the question, reason i havent replaced the factory airbox is the problem with heat in the engine bay i dont want my filter to suffer from heat soak, i was thinking of getting a custom aluminium air box made and have a pod filter placed inside or possibly purchase the ARC super induction airbox, i noticed that your filter just out in the open, but i guess you are running twin fans to keep things cool.

I was also searching old threads trying to find info on stages of modification, i would imagine progression would be exhaust,dump pipe,filter would be the starting point after that whats next, i was kinda thinking of possibly throwing $10k tops on the engine in the next 12 months, i dont want a lag monster im thinking of keeping the ct20b i think i would be happy with 300-350+HP and neck snapping acceleration.

Sorry for the long essay lol but youve been there and done that any advise would be appreciated.thanks in advance

After you factory air box do you have the AFM(MAF)? If so, you do not have a Gen III. I suspect that you may not.

If you have the AFM(MAF), then I would not recommend venting the BPV to atmosphere unless you get a VPC or an EMS.

If you do not have the AFM (or you get rid of it), this mod is simple.
Buy a filter and stick it on the BPV. :) ... and cork the hole that used to go into the intake.

Air filters, I would only recommend K&N or Apexi. I am a big K&N fan myself. The HKS are garbage.

Downpipes are a waste of money IF you are planning getting a larger turbo later on. If not, the are a great mod for the OEM Turbo.

Worrying about heat soaking the air filter is nothing nothing to worry about. No matter what happens to the air prior to entering your system, it is still going to go through the turbo and get compressed which will drastically increase it's temperature anyway. That's why we have intercoolers :)

350 rwhp from a CT20B is expecting a lot and you will be taxing your system to get there. In reality, it takes quite a bit just to get to 300-317 rwhp with the CT20B.

If you want to read the "MR2 Bible to upgrading," see here:
http://www.mrcontrols.com/primers/power.htm

Thanks for the reply, no i dont have an AFM after my airbox it just goes straight to the turbo, correct me if im wrong gen III engines usually have a silver plaque ontop of the throtle body while the Gen 1&2 which has red and black twin entry turbo badge inastead.

I will probably go for the Apexi filter which i was thinking of geting anyway, so by the sounds of its probably a better idea to spend the money on an intercooler rather than a dump pipe if i was to go to a turbo upgrade, which is most likely,should i waste my time on the ct20b or go for an upgraded turbo straight away, is it easy to get to 300rwhp on the ct20b?. what turbo are you running just by interest?

ive also heard of mods regarding the machinining of the throtle body 2-3mm on the gen 1&2 engines to increase air flow to the throtle body, does this mod apply to the Gen III, is it worth doing?


Thanks again for your help, i really appreciate it.

If you do not have the AFM, then I believe you do have the Gen III.

Whether or not to upgrade your turbo depends on your goals. What do you want your car to be able to do?

I have a custom T3T4 turbo. The stats of it are on my site.

ATS Racing makes a larger throttle body inlet. Click the photo in my siggy to get to them.
I'm not sure if the Gen IIIs already have an improved TB or not.

After that intake, Get a nice intercooler, up the boost to 14-15psi and then tell us how you feel. If you're comfortable with that kinda power just get the downpipe and be done with it, if not you know you're going to want a bigger better turbo, like the T3/T4 or a TD06. Those kits will come with a downpipe...

(This is all assuming your state is Lax with emissions.)