Crxsir123

Ok I've done a lot of searches but still have some un answered questions... How do I convert my 91 CRX SI d16a6 to obd1 without going vtec?? And I want to use p29 pistons and a d15b7 head to raise the compression but what head gasket do I need to keep the compression safe enough for a fast *** sohc non vtec daily driver any other suggestions would also be appreciated! Thanks!

alsims86

I'm just curious why not run a z6 head if you go obd1? I had an a6 short block milled .015 and a z6 head combination with just bolt ons and a tune in an eg coupe and it ran right with a Jdm b16a swapped eg coupe. But to each his own and a non Vtec would be more impressive IMO.

hondamark35

This is all fresh in my mind, i've spent the last few weekends swapping a Z6 into a DX Wagon (dual-point)! much easier in your casen as half the work is done with it being an SI. just follow any of the conversion write ups (or, like I did compile as many as you can find into one big stack of info) for going from OBD-0 to OBD-1. don't wire up VTEC- physically running the two... three wires, and don't use a VTEC ECU. that's all there is to it.

the right cam and set up will keep the dynamic compression where it needs to be. online calculator shows about 10.8:1 if you run a stock-thickness HG for the A6. it also shows that the A6 and B7 have the same chamber volume, so i am not sure why you would change that out...

Crxsir123

because people have told me the d15b7 head will also raise compression I just have to keep the a6 cam... I also know that I can keep the complete a6 motor and add p29s and a z6 head gasket and it will either be 10.1:1 or 11.1:1??

Crxsir123

I might just do the p29s and keep the whole a6 engine and use a bisi cam and some other tricks maybe a y8 intake manifold and a b18 tb but how would I do the map sesnsor since the a6 one isn't on the intake manifold is the map sensor attached to the y8 one???

Crxsir123

I just used the d series compression calculated if I stay d16a6 and run the p29s with a y8 or z6 head gasket it will put the compression to 11.10:1 is that safe for a daily driver? And if so what hp am I looking at? And what is the difference in the y8 and z6 head gaskets which should I buy or does it matter?? And if anyone knows of any other tricks to make the a6 faster plz let me know!

hondamark35

the connectors for the MAP sensor between the two are the same. in most cases you can just unplug from the firewall MAP and plug into the TB mounted MAP (both Y8 and B18 pretty much in the same location). the wires do just reach, so for piece of mind you may want to extend the wires a few inches. a little slack will keep the wires from pulling out when the engine rocks forward.

like I said at first, cam specs and set up will determin your final dynamic compression, which is the one that matters. 11:1 static can be run with premium fuel as long as you have the car dyno tuned to avoid detonation.

esteen2

NPR and Ycp p29's have different compression heights and dome volumes. I would keep the non vtec head, get a Colt cams tri-flow 2 cam, z6 head gasket, NPR p29's, ARP rod bolts, Supertech valves, Isky springs, z6 intake and throttle body, a good 3 angle intake - radius exhaust valve job, a nice header, and a good tune on obd-1. Should be around 11.6:1 compression which is fine on 93 octane.

ApexiChild

impossible
there is no fast dd sohc nonvtec out there.




pick your piston/compression based on your fuel type.

esteen2

What do you consider fast?

ApexiChild

sorry I didn't mean to offend anyone.



don't get me wrong, i'm all for the underdog engine of the stout A6.
If built right an a6 could make +150whp while still being "streetable"..... and maybe 22mpg , idel of 1400'ish rpm, would be very respectable to OG honda guys IMHO.

HOWEVER, i wouldn't call it "fast" when you compare it to stock k, mild lsv, gearing of b tranny..... I think not.


The idea of making a a6 "fast" is cool.... heck maybe even fun toy.... but the task is not to be be taken lightly. OP has yet to discover how to convert to obd1 let alone a custom fast engine. I just don't want OP to start on a path that he'll more likly bail out on.

my intentions are good.
But this is 2014, there are countless other more cost effective options out there.
Unless your married/hardcore fan of the a6, I cannot convice my customers or other noobs to go through with pouring money into an a6. believe me, it took me a while to convince myself out of it too.


the a6 will always have a spot in my garage. = )

esteen2

My previous d16a6 made 157hp and got 32mpg, but it wasn't cheap.

ApexiChild

Niiiiice.

so 157hp. i'm assuming that's on a engine dyno not on a dynjet or something right?


the last a6 i did like 4yrs ago made 135whp... kind fun to drive around in.
It was for a old buddy who use to be into cars and just wanted to play around an engine so we spend about $600-650 includes parts & machining. had it been someone else who had to pay full price for machining, labor for engine builder or didn't have proper tools it would probably cost about $900-1200 (machining & engine builder price may vary).

I was happy about the motor but i cannot tell if he was really satisfied.
Finding 30% gains in engine efficency is not like bolting on i-h-e lol.

To put things in perspective i did overlay his dyno chart with a stock crx si a6 which only made 92-93whp, so that did chear him up to know his $600 was well spent. I told him "Import Tuner ain't gonna show you that kind of return on your money"..... - pre 2004 magzine stuff they use to always do "spend $999 & get 14whp on your honda"

esteen2

No, that was on a chassis dyno, but who knows how it was setup. We all know some shops read higher than others. Like I said it wasn't a cheap motor and it had lots of compression.