hey guys, this is my first post here and i read the rules but if i mess up just let me know and ill correct it.

well my name is patrick, im 18 and i live in san antonio.
i bought a '90 CRX Si back in august but blew the d16 in like a month (in my defense it did have 260,000 miles on it).
i swapped it with a ZC DOHC and have been slowly adding bolt ons (tanabe concept g exhaust, 4-2-1 headers, Random Technologies Cat, Tenzo R CAI, front upper strut bar, c-pillar bar). its been a blast to drive and i wouldnt dream of selling it, but im looking for a little more power. im not out to be street racing and killing myself and others, but it would be nice to make some respectable numbers at the track. so at this point i've got 2 questions.

1. is there any v-tec head at all that is compatible with the block on my zc?

2. what are the absolute necessary preparations i need for my engine before i start running boost. i've heard plenty of horror stories of boosted civics melting down cause the engine couldnt handle the boost.

i know you guys know what youre talking about here and i would really appreciate your help.

 

To the best of my knowledge there are no swapable VTEC heads that will fit on a DOHC ZC. I suggest you check out www.thezcr.com. which is a web site devoted primarily to the dohc zc. Lots of info if you use the search function. Good luck

 

my brother has a dohc zc running 10psi of boost from a t3/t4 57 trim turbo.
As long as its tuned right you can run up to 12psi stock.....might have to do your clutch

 

Head gasket will need changing as the ZC's gasket sucks bad. Other than that if you buy quality parts and have your car tuned professionally you should be ok. In all expect to drop 3 grand on a properly built and tuned turbo set up.

New clutch
Headgasket/ head studs
turbo
Turbo mani
Charge pipes/Exhaust
Intercooler
BOV
One step colder spark plugs
Gaskets(intake/exhaust)
Injectors(450 and up)
Good tune!

Thats about it plus or minus a few things. While your at it you might as well do the water pump and timing belt when the head is off. Also now that you can go fst you need to be able to stop! A brakeupgrade is now in order. Once boosted your car will most likely overheat cause of the underhood temps so an aftermarket rad would help. But wait theres more! In order to fit you new "cool"rad you will need a traction bar set up......

My point is there is no end once you have a boosted motor. Not to mention all of the parts that go due to wear and tear such as tires. Cv shafts, distributors. Turbos are fun but not for the cheap or poor!

Rick

 

thank you guys! yeah i checked out that site and didnt see anything about making a dohc zc vtec. but yeah i hear what youre saying about the turbo. the list of mods is just the fun stuff ive done. ive put a total of 7 grand in this car, plus the 3 i bought it for. ive replaced the cv axles, water pump, thermostat, housing gasket, and all pads and rotors are brand new. im gonna be tearing it down for paint soon so ill post up pics, but thanks again for the help guys

 

On some clarification for selecting parts for turbo;
You should figure out what hp you want to make. The ring lands on the pistons and the rods are the weak points to our motors. People generally agree that the rods are good for about 250hp, but I personally wouldn't go as far as to say that the motor will last like that. Most people shoot for about 200hp for a daily driver D-series.

You select your turbo by the hp numbers. Trying to figure out what psi a motor can handle means nothing. Different turbos put down different hp at diffent psi. You can obviously go with turbos that others have had success with on a motor setup similar to yours. OR you can learn to read turbo flow maps... lots to learn there.
You also select the injectors by your goal hp number. 450cc is about right, but 410cc would do fine. http://www.injector.com/injectorselection.php

Tuning tuning tuning!!!
Get it TUNED (more money to consider into your budget).
Don't risk it by running off a basemap.

 

well my goal is kinda lofty i guess but id really like to see my rex make something like 285hp. i know this isnt you guys' job but if anyone could recommend some good parts for my kit and any other parts that might need to be replaced to handle it, i would really appreciate it. im not on too tight of a budget but im no millionaire so yeah. thanks guys

 

Sounds like you are in my type of situation. I have done tons of research for well over a year, and I am still going to let it up to the people at go-autoworks.com when im done getting the money together. They will get you a great kit perfect for your setup and goals with no guesswork involved. Just my 2 Abes.

 

yeah sounds good to me cause this will be there first car ive had running boost besides an '86 300ZX so im scared ill get a kit that will just blow my engine sky high. probably gonna leave it up to the guys at Scorpion Auto Designs cause they did my swap and everything else and both the guys there run boosted rex's so im gonna trust them.

 

Even if you did manage to put a VTEC head onto the DOHC ZC, you wouldn't gain any power. It's one of the most powerful D engines.

The SOHC VTEC head's have very similar power figures, so it would be a waste of time trying to get one to fit.

 

285 hp? Sounds like you need pistons and rods as well.

 

yeah i figured that about the pistons and rods. any certain brand you would recommend?

and yeah the guys at the shop just told me today about adding vtec being a mute point cause it really wouldnt do anything.

also, does anyone have any idea where i can find an EDM Si spoiler besides ebay?

 

There is no dohc zc vtec,but there is a single cam zc vtec.My advice is get your zc boost and tune.

 

yeah i think im just gonna build it up, boost it and tune it.
vtec is great but i dont need it to have a quick rex.

 

Word

 

285?
I think you can do better than that.
Say... 350ish limited to the turbo parts you buy and the tune you get!

For the bottom end I'm thinking;
Vitara pistons
Aftermarket rods (eagle would be my personal choice)
ARP head studs and rod bolts
Balance rotating assembly and micropolish crank
Bored oil pump
New bearings gaskets and seals.

Could probably get away with minimal head work;
Cams
Mild port and polish

If you go eBay on the turbo manifold, get a cast one! The welded ones are prone to breaking. leaking, cracks...etc due to cheap welds and cheap material.

Injectors would need to be about 600cc for 300hp (adjust 100cc per 50hp).

Info on Vitaras.
https://honda-tech.com/forums/forced-induction-16/more-info-suzuki-vitara-g16-pistons-954478/