Use 6" small journal Chevy rods with custom pistons. That will get you a 1.16"ish compression height.
There is no "ideal" ratio.
If you want to make power, go to aluminum heads.
Well, half the fun is mixing and matching off the shelf parts. I think my whole point about the ideal ratio is what one of the articles I said linked: when certain options are limited (ie stroke, heads, etc..) then you optimize what you can. In your statements, you are not limiting your engine build in any engine manner where as I am specifically talking about the engines available to us from the cars we buy. So I am saying "There is no ideal ratio when your options are unlimited." In the real world, we make the best of what's actually available.
I may replace my 4.9 with a 3500 when it finally dies but in the meantime with my race car, I will be changing as few parts as possible. Changing to aluminum heads means changing alot of other things too. I want to just rebuild this block, get new rods and off the shelf TDC pistons. I'm currently .020" over bored. I can still go to .040 or .060 on the next rebuild.
lou_dias
DEC 19, 01:45 PM
Another mod I might do for the next racing season is going from a cast iron Trueleo intake to an aluminum one. Francis gaveme a stock S curve for the neck even though I told him I was going to DIS. Right now it's preventing me from running an air filter as the deck lid hinge is right infront of my L98 throttle body. I need it to come out, then turn right 45 degrees and aim down to where the stock filter housing used to be.
You can see how that air tube gets bent when the lid comes down... :/
[This message has been edited by lou_dias (edited 12-19-2012).]
34blazer660
DEC 19, 03:12 PM
cast iron? i think thats DOM steel welded together. all the money you would spend installing an aluminum intake you could easily swap to a 3400/3500 topend and make another 30hp over the restrictive iron heads.
lou_dias
DEC 19, 04:49 PM
quote
Originally posted by 34blazer660:
cast iron? i think thats DOM steel welded together. all the money you would spend installing an aluminum intake you could easily swap to a 3400/3500 topend and make another 30hp over the restrictive iron heads.
Well, my heads aren't that restrictive. I've had them ported and polished to be close to Falconer heads, which have supported 275 hp. I haven't done a dyno recently since I started doing my own tuning but I can tell you I'm making more than the 187rwhp that I made when I was running the Fiero intake and 57mm throttle body... As you can see, I easily keep up with a modified WRX:
34blazer660
DEC 19, 05:51 PM
the video really doesnt prove anything. falconer heads? one fact remains, GenIII heads>irons, any day of the week. id like to see the ported irons outflow untouched 3x00 heads lol. easy to get to 275hp with boost
lou_dias
DEC 20, 07:54 AM
quote
Originally posted by 34blazer660: the video really doesnt prove anything. falconer heads? one fact remains, GenIII heads>irons, any day of the week. id like to see the ported irons outflow untouched 3x00 heads lol. easy to get to 275hp with boost
GM built a 2.8 with 14:1 compression with iron heads ported by Falconer that put down 275 hp. This is a known fact. In stock trim, the aluminum heads outflow iron heads. However, a proper port and polish can accomplish much. You say the video doesn't prove anything, well a bone stock WRX can do the 1/4 between 14.0-14.7 seconds. I know the guy in the video is not stock, but not heavily over-boosted either. Another example: http://www.youtube.com/watch?v=hP-x76mXHNY he had a killer launch, I didn't have my best launch http://www.youtube.com/watch?v=Yg4TPeitJBU last year he had a bad launch and I had a good launch and I beat him from the outside lane
Now I'm not claiming to be a 12.x second NA 3.4... I'm not claiming to be a 13 second NA 3.4...I'm not claiming anything other than the fact that these cars who are proven fast cars are not embarrassing me in any sense of the word.
Look here at about 13:35 and you'll see me go against a modified Ford Lightning. I babied it in the 1st round because I smoked him off the line...until I saw him next to me. In round 2 I almost stalled at the launch but then didn't let off. http://www.youtube.com/watch?v=rLidp-lIQpM
Say what you will about aluminum vs iron heads, all I know is I can't complain...
Joseph Upson
DEC 20, 08:18 AM
Did someone say high compression? Do it. I'll never cripple another motor I build with stock compression specs if I can help it. That's cheap and effective performance improvement if anything is.
[This message has been edited by Joseph Upson (edited 12-20-2012).]
34blazer660
DEC 20, 02:41 PM
quote
Originally posted by lou_dias:
GM built a 2.8 with 14:1 compression with iron heads ported by Falconer that put down 275 hp. This is a known fact. In stock trim, the aluminum heads outflow iron heads. However, a proper port and polish can accomplish much. You say the video doesn't prove anything, well a bone stock WRX can do the 1/4 between 14.0-14.7 seconds. I know the guy in the video is not stock, but not heavily over-boosted either. Another example: http://www.youtube.com/watch?v=hP-x76mXHNY he had a killer launch, I didn't have my best launch http://www.youtube.com/watch?v=Yg4TPeitJBU last year he had a bad launch and I had a good launch and I beat him from the outside lane
Now I'm not claiming to be a 12.x second NA 3.4... I'm not claiming to be a 13 second NA 3.4...I'm not claiming anything other than the fact that these cars who are proven fast cars are not embarrassing me in any sense of the word.
Look here at about 13:35 and you'll see me go against a modified Ford Lightning. I babied it in the 1st round because I smoked him off the line...until I saw him next to me. In round 2 I almost stalled at the launch but then didn't let off. http://www.youtube.com/watch?v=rLidp-lIQpM
Say what you will about aluminum vs iron heads, all I know is I can't complain...
wow 14:1 compression, thats crazy for the street lol. im sure it put down some power, probably really good torque with the compression, of course. im also sure reworked irons will flow way more than stock, which is good for a mild street build. iirc, a little bowl work and some light polishing on my irons(from weber racing), gained ~30 cfm over stock numbers. peak flow on the intake was somewhere around 180 cfm on the intake at .500 lift. once i went in and port matched and opened up the entry, im sure its around 190ish cfm. either way the Gen III heads are far superior due to the revised ports and canted valves. a member on v6z24.com built an LX9 with ported heads, tuned, cammed, etc, put down 275whp thru the getrag. thats around 315 at the crank N/A. if you had a similar setup you would be hard to catch in the class you race in. youre already most of the way their with the 3400 bottom end, DIS and 7730. even marsman put down 225ish WHP with his junkyard N/A 3400. once you decide you want more power, there are more options out there for you.
lou_dias
DEC 20, 04:59 PM
Like I said, my last good dyno was with the Fiero intake and that did 187...I should be over 200 with the Trueleo intake, just don't have a dyno yet because the car is awaiting a frame-straightening from the collision with the Ford Lightning.
The other factor in this is I don't want to spin this motor past 6000rpm. I like the torquey nature of it. Right now my clutch dumps are at 3000rpm. I need to add a bit more timing from 3000rpm and below because I had pulled timing when I had a bad tune from Darth. I've since realized that with my current 9.85:1 compression, that super unleaded isn't good enough and now add octane booster but I never added the timing back from when I was detonating like crazy. If I drop the clutch marginally above 3000, I launch perfect, if it's just below, I bog down to 1000RPM and you can see this in some of my launches.
I think going to ported aluminum heads I may lose more bottom end and hurt my launches....which are critical on this type of race.
lou_dias
DEC 21, 05:00 PM
Ah found the video where I beat the 12.451sec 1/4 mile eagle summit. He bogged his launch and I nailed mine, vs. the reverse of when he beat me...
