Which Cylinder head?

[niterydr]

My advice is no good, please delete.

[HiImBrian]

Holy novel! Dang swanny writes a friggin book and doesn't once comment on my idea of an evoIII head. I was kinda hoping to see some feedback. shux

[Shane@DBPerformance]

I like the 2G head, it seems to make good power. The 2G intake manifold and 2G throttle body suck though. I wouldn't run it in a performance application without doing a 1g TB and sheetmetal intake though. The 1G heads will "flow" more, but that doesn't mean they will make more power. A smaller port can often do a better job getting more air into the cylinder, due to velocity than a big port that flows a lot on a flow bench.



I want to go to E85 for the 108 octane so I won't be dealing with knock but still a little confused on what I need to do to the car to make it compatible.


You will still have to deal with knock.


There was a test done on a turbo Honda with 10.0:1 compression versus 9.0:1 compression on the same car. At 10.0:1 it made a little more HP at the same boost level, but they could obviously run a lot more boost with the 9.0:1 pistons. Turbo spoolup time wasn't really affected at all.

You are going to need some big injectors and possibly 2 fuel pumps, if you plan on making a decent amount of power on E85.

[Andrew7dg]

Doesn't everyone on this forum like to discuss theory?

I am very glad you people do... It is getting rare to find people wanting to talk about engine stuff or do anything with engine anymore.


So what I got from niterydr is that there has to be a balance between the port size and the velocity of the air going into the engine. Basicly this all depends on the hp of the car. I didn't know about the term "sonic choke", good thing to know.


I should have used a subject matter like this I should have used a better example then 2g vs 1g. Yes they both use a 4g63 but when it comes down to it, there are a lot of changes between the 6-bolt and a 7-bolt 2g engine.


The whole tuning theory is for another thread. Be glad though that I have realized that instead of using some cheep tuning device, I am using a standalone system taking control of everything plus a wideband. Unfortunatly I don't have a ECU that is an Eprom, or the money for dsm link. I compaired prices and features of both and my decision was to go with the MS system. I do realize that money spent on tuning will make this car "perfect" A car won't run right without the proper tune. Money I will save from going with the MS system will probably go right back into tuning the car.

I should pick a turbo now. I have been avoiding picking a turbo because everyone has their own opinions on them. I should figure out what I am going to go with. then match the engine to it. I still don't know what to go with though...

With E85 I do know that I will still be dealing with knock. I should have specified on this more. With running higher compression pistions and running low grade octane (say 91) I will be having problems trying to tune out knock. Like you said, the pros of E are higher grade 105 octane (sorry about the miss information). Question is though, how bad does the grade of E fluxuates? this could completely mess up tuning.



niterydr- I didn't take it as being picked on, and I hope you weren't picking on me too much:).
I hope this thread isn't just to educate me, I hope there are other people getting information about this as much as me.

[Swifty1638]

To the above who posted it. At the shootout, Brent was telling cher amd myself that he had to swap hos ol' trusty head, because it was machined beyond specs. He didn't have another head, so Marco gave him a 1g head. He left the porting alone, but obviously swapped in his springs retainers, cams, etc. Ran a 7.13 on the car with it. So, that's were I stand. I'm more worried about the air outside of my motor going in (IE intake manifold-shitty) etc, rather then the dynamics of the 1g head taht currently resides atop my block. I am, however, interested in the theories presented behind al of this madness. Does anyone know of other heads that would/could bolt up, or even be modded slightly to work?

-A. Swift

[DBMajik]

With running higher compression pistions and running low grade octane (say 91) I will be having problems trying to tune out knock. Like you said, the pros of E are higher grade 105 octane (sorry about the miss information). Question is though, how bad does the grade of E fluxuates? this could completely mess up tuning.


I don't like the way you put "I will be having problems trying to tune out knock"

No, you really won't. It's the same as tuning a 7.8:1 compression motor, only with less boost. My recent setup was pushing 20psi with the exact same timing and almost same fuel as my old stock motor. Only the stock motor was running 22psi.

[Andrew7dg]

You are right. I don't know what I was thinking when I made that comment. For some odd reason I was thinking if i were to run the same boost pressure, not even thinking I should be turning down the boost. There is a trade off there.

I forgot to answer what I made my boost controler out of,
T fitting from an air compressor. On the top part of the T, there is a screw that controls the tention of the spring and the spring rest on a little metal ball, like the size of a bb. The bb ofcourse blocks air off untill it reaches a certain pressure where it lets air travel to the bottom of the T and that goes to the waste gate. I have a picture. I should just post it. less then $20.00!

What other questions did I miss, The hard pipes are SS (i will measure it later). I am not sure how the end tanks on the FMIC are going to work, they will work but I just don't know how well... I don't know if I like the design... It is a greedy core with for a 2g with the end tanks cut off and some new ones welded on to fit a 1g. I know there was a big discussion on end tanks not too long ago.

On the hard pipes, there is a flange designed for a DD blitz blow off valve. Came with the intercooler and hardpipes. I think I am going to have to change the spring so it handels over 18 psi. I haven't seen too many people use them so I don't know how it will work.

Just want to say thank you for clearing up a lot of miss information for me. I feel kind of dumb asking questions like these sometimes but it is the only way I will learn on how stuff works!

[xveganxcowboyx]

This has been an interesting read. I've done it in stages so forgive me if I missed this, but... Has anyone asked whether this is even worthwhile? I'm sure there are tons of variables that go into the performance differences in the various head (4 mentioned so far), but I'm thinking that outside the world of theory or huge builds this is a useless subject. If there's no large and clear advantage to one or the other why not just leave the stocker on and invest the time and money elsewhere?

Maybe I'm off base saying "what's the point," but if it were me I could come up with a few dozen things to spend my money on before worrying about the minor theoretical differences that would justify a head swap.

[DBMajik]

On the hard pipes, there is a flange designed for a DD blitz blow off valve. Came with the intercooler and hardpipes. I think I am going to have to change the spring so it handels over 18 psi. I haven't seen too many people use them so I don't know how it will work.

About those Blitz DD's. Every single person I know that owned one sold it because it leaked. I'm not saying don't try yours, because it very well could work. I'm just giving you a little forewarning if you haven't bought it yet.

[Jakey]

I'm more worried about the air outside of my motor going in (IE intake manifold-shitty) etc, rather then the dynamics of the 1g head taht currently resides atop my block.
You'd be amazed at what CFD modeling can tell you in terms of how much a shitty port job can really hurt you.