SlowRider

Hi. I have a D15b7. Would it be better to do a d16z6 head with a 55 shot of nitrous. Or a d16y7 Port And Polished head with a 75 shot of nitrous.( I dont know if you can use this head so elighten me.) I am worried about the vtec with nitrous because of the higher compression wouldnt it blow the motor..I dont want to do a full swap and I want to stick with the D series. I already have a EX Tranny...Please serious answers and No swap to a B series Answers I want to do something with my D series to many people have a B series swap around where I live.

Redcivic

No problems using a VTEC Head with nitrous, you'll actually get more out of the shot. The main thing is fuel control, I would get a adjustable fuel pressure regulator and an air/fuel ratio guage though. You can get a decent dry set-up off ebay for around $279.00, don't waste your money on a $700.00 nitrous express or NOS brand kit. Then just get a NOS brand nozzle because the cheap nozzles suck. I got the NOS brand nozzle and a 75 shot jet for $11.00 from a local domestic shop. With the VTEC Head you will get a little more HP and it's more durable than the non-VTEC head. I also recommend a window switch that deactivates the nitrous at a certain RPM so that if you over rev (mis a shift ), the nitrous is not spraying when you redline.

SlowRider

Sounds Good to me. Thanks for the info. If anyone has anything to add please do.

oc_civic

i would get an egt of fuel pressure gauge over an a/f gauge...

an egt will truely tell you how lean or rich you are

and a fuel pressure gauge will tell you if your fuel pump is spiking, or not flowing enough gas

and while you are at it.. if you are still on the stock pump id get an aftermarket one.. since fuel pressure almost doubles on nitrous (around 40 off nitrous and close to 80 on nitrous)

SlowRider

Great thanks alot. I would like to hear more answers and opinions on this so please keep the coming. I would like more answers on wich combo I should use...

builthatch

Either of these, w/o calculating, will give you (i am guessing) about 10:1 static compression ratio if my memory serves me (both heads have 34.6cc volume i think)...
Get the z6 head if it is in good condition. It breathes well stock and vtec is always a nice feature on a street car. I would say spend the money on the NX kit, run a 60-70 shot, run heat range 7 plugs (like NGK BKR7e-11) and retard your timing a few degrees, the whole time consult an expert to make sure the car is running well during juice runs (check plugs, etc...)

stuff like fuel pressure gauges, egt gauges, etc are not necessary with such a small shot and basic (unbuilt) motor...if something is going wrong on a juiced car, especially an mostly stock motor, by the time you see it on your gauge, it'll be toast anyway...the only mod besides the colder plugs i suggest would be maybe a higher flow fuel pump like the walbro 190 or 255, or atleast a unit from another model, i am not sure (again, i forget), but i believe the stock cx unit from 92-95 is very weak...also, the window switch is not a bad idea, especially if you have a stock revlimit/fuel cut...

SlowRider

Can I get The same power out of the Y7 head and will this head work.? If it would do the same thing then it would be better because there would be no additional wiring or computers or anything.. Please let me know.

builthatch

well, i did not consider before that the original motor was not vtec. I take back what i said about using the z6 head because any gains by using the vtec head would be negated unless you used the proper vtec ecu, which would mean converting over to a p28 (obdI sohc vtec ecu) and running the few lil wires needed for the vtec function..even a vafc slapped in there to control vtec and the fuel would not help much since the timing maps would still be off, so in short, the vtec head would be better than the y7 only if you did it right in terms of engine management, BUT, for your case, to answer your question, the y7 head would work better than a ghetto rigged z6, however, the cam timing of the stock y7 cam is HORRIBLE, but nonetheless, i think the 75 shot would provide the boost you are looking for even if the y7 head was not ported.