I'm still trying to completly understand Compression Ratios, and have a few questions. First off I'm going to be rebuilding my engine this up comming summer, so over the winter I'm going to collect all the parts I need for the rebuild. I have a 97 2.4LD9 and I'm wanting to put the 086 Head on it with the HO Intake manifold and HO 56mm TB. I'm also going to get the HO cams for maybe the Secret Cams which ever works best. I'm also going to be getting forged rods and pistons from car customs. I know the 2.4 has a CR of 9.5:1, I have no clue what my CR is going to be with the 086 Head. I think I figured it would be around 10.1:1 but I'm sure I'm wrong. Getting on to the point I want to build my engine up for turbo and be able to run 10-15psi. With forged internals, the 2.3 Oil Pump, HO Cams, 086 head, HO Intake Manifold, and all the little stuff needing to be done what CR of Pistons should I look at getting to keep my CR lower for turbo? I know I'm going to have to go with a 91 Oct. and higher fuel after everything is all said and done. Can anybody give me an idea of what pistons to get with my setup, and still keep the CR around 9.1:1 - 9.5:1? Or is there a diffirent Cr I should be looking at going for with the setup I'm wanting to do?
In the planning stage for an all American TRD Cavalier.
It's a myth that you need to lower compression for boost. People need to stop thinking that.
You can run 20psi on 15:1 compression. It's all in how you tune your car.
A stock 2.4 piston with a 086 head will give you 11.4:1 compression.
Gilles
2.3 Ho
Lowering compression with boost allows you to use lower grade gasoline and spend less time tuning. However, it also creates a 'peakier' torque curve, and you lose the 'area under the curve' that you get from higher compression.
Also needed to be factored into the compression ratio is the intake camshaft being used. While it doesn't affect the static compression ratio (like you're referring to), it does affect the dynamic compression ratio (what really matters). Of course, camshaft selection on turbo motors is important in a totally different (and much broader) aspect as well.
fortune cookie say:
better a delay than a disaster.
I'm doing the exact same setup right now and Karo sold me a set of Wiesco 8.4:1 pistons which will give me about 10.2:1 static cr with the 086 head. I also am going turbo but I'm going to use modified W41 cams ( for ps hex and cam position sensor) and HP Tuner software.
Your compression with the 086 head will be approximatly 1.8 points higher than whatever your cr with the stock head.
2000 Z24 5spd header & catback for now.
Glad to get your input Dale, I'm glad to hear from somebody that is doing the same setup as myself. But for me I'm going to use the HO Cams I have heard to much from poeple that they use the W41 Cams and the car does not run right at all. Even Karo himself could not get his car to run with W41 Cams. But I will also be using HPT to tune my car. Even with a 10.2:1 CR I'm probably gonna be running better than 87 Oct. fuel.
In the planning stage for an all American TRD Cavalier.
I guess I am still at a loss as to why people try to get 2.4's to be 2.3's? Why not just use the right engine from the start? It was meant for high rpm, higher HP use. Get a 2.3 HO and use it. Why pay for all the modding of the 2.4? Maybe that is just me though.
Sven you totally quarterloafed your computer..
Well in my case my car is a 2000 Z24 and is my daily driver and it still has to pass emissions and such I can't just swap in an older engine, also I want to ensure that all my sensors are there and in working order which may or may not be possible with a complete 2.3 swap.
Also many people here and other places seem to think that the 2.4 engines are junk and incapable of making good hp/tq, in there minds if you don't have an ecotec or a quad4 2.3 you're not worthy of mention. I intend to prove them wrong.
When I first described my turbo buildup I was told by members of this board that I'll never get in sniffing distance of 500 hp, my engine builder laughed at me and asked if all I wanted was 500 because with the airflow of the 086 head and W41 cams I could make much more than that. The reason I'm limiting myself to 500 - 550 is because I'm using a stock nodular iron crank, if I had $2000 to spend on a billet crank I'd shoot for 750hp.
2000 Z24 5spd header & catback for now.
Jrobz23 wrote:I guess I am still at a loss as to why people try to get 2.4's to be 2.3's? Why not just use the right engine from the start? It was meant for high rpm, higher HP use. Get a 2.3 HO and use it. Why pay for all the modding of the 2.4? Maybe that is just me though.
2.4's have a higher displacement which means more power,
2.4's have a longer stroke which means a flatter torque curve
2.3's with a 2.4 crank rule all.
My father and I did all of the work on my car, with the exception of getting the block bored and everything balanced. So there was no added expenses.
cr with stock internals and a 086 head is 11.25:1
HO cams are w41 cams
750hp? I honestly don't think the engine can produce that. MAYBE with cryotreated everything, titanium rods and crank, high cr with monster booost and the greatest tune ever achived with a stand alone, but no one has even gotten clost to that. 400whp is atainable with boost, which is about 470bhp, but still that stock tranny might not be happy with you.
- Paul
Paul your info isn't correct swapping a 086 head onto a 2000 2.4 which has 9.7:1 will put the cr at 11.5:1 and the HO cams are 212*/212* duration -.410/.410 lift and the W41 cams are 219*/219* duration .410/.410 lift so they are not the same.
2000 Z24 5spd header & catback for now.
Also the big limiting factor to making big hp/tq with the 2.4 is the sorry stock head, of the people you mentioned how many are using the best flowing head, the 086. Most of the people you're speaking of are using a ported 2.4 head, which still can't flow as much air as a stock unported 086 head, that's why they aren't making more power. Jim Fueling made 1000 hp with a turboed 2.3 Quad4 HO and set a Land Speed Record with it back in the day. And since I'm using the same head & intake he is I could make as much power but the limiting factors are I don't have a billett crank and the stock trans would die for sure under that much power.
2000 Z24 5spd header & catback for now.
Dale Young wrote:Paul your info isn't correct swapping a 086 head onto a 2000 2.4 which has 9.7:1 will put the cr at 11.5:1 and the HO cams are 212*/212* duration -.410/.410 lift and the W41 cams are 219*/219* duration .410/.410 lift so they are not the same.
Thanks for the correction, i tried searching quad4forums for duration but all i found was that they were the same. As for cr, i did the calculation with these numbers,
LD9 LD9 w/086
Bore 3.54 3.54
Stroke 3.7 3.7
Head cc's 60 48
Gasket Thickness: 0.047 0.047
Deck Height 0 0
Dish or Valve Pocket [-] or Dome [+] cc's: -2.6 -2.6
Piston Volume 36.41649381 36.41649381
Piston Volume (cc) 596.7594147 596.7594147
Gasket Volme (ci) 0.462587894 0.462587894
Gasket Volme (cc) 7.58045743 7.58045743
Compression Volume(Head cc's + Gasket Thickness+valve pocket 70.18045743 58.18045743
Compression Ratio 9.503213524 11.25704233
Didn't the cr change from 98-99?
And i forgot about jim fueling, i've read the article, it sounded like an awesome motor. The only reason why i'm not using that head is because in order to get it down to even 9.5 cr i'd need a 7.5 cr piston and i have yet to find one. I know you can boost a high cr motor, i'd rather stick with something around 9-9.5 though, still working on the calcs for that though.
- Paul
Yea Paul the 2000 and up LD9s have 9.7:1 cr instead of 9.5.
2000 Z24 5spd header & catback for now.
Brian Whalen wrote:
2.4's have a higher displacement which means more power,
2.4's have a longer stroke which means a flatter torque curve
ok I'll trade my .1L for better timing chain setup for high RPM, cam gear option, better head, better oiling, better bore/stroke ratio for real POWER (not low end tq which is useless FWD IMHO), and a forged crank option, and possible race block with oil squirters for piston cooling. Hell I have a 2.4L in my car and I love its TQ curve, but if you wanna shoehorn a high power 2.4L on the street then get ready to drive on slicks or replace timing chains every 10 minutes of full boost/rpm use. A 2.3 HO based setup will hit max TQ much higher making launching easier. Plain and simple, the 2.3 is a better platform for real power than the 2.4. Don't try and prove me wrong because you won't.
Also, there are ways to get your 2.3 in your 00+ and have everything be stock and working. It's been talked about at nausem by myself and others. If you are worried about emissions then put the 2.4 IDI cover on and run your MSD cables beneath it (you'll want wires if you shoot for 500HP). No one will ever know it is not a 2.4L. Problem solved.
Ask some of the people who have put the time and money into a 2.4 to get it up there, and they will tell you that it would have been cheaper to go 2.3 to get there with the end result prolly being more stable. if you wanna rev your car high enough to drill your block and convert for a 2.3 oil setup you should swap instead IMO.
Sven you totally quarterloafed your computer..
Jrobz23 I don't doubt any of the points you make but at the same time your thoughts are one of the reasons that I am building my engine this way. I hear many people say the 2.4s are worthless compared to the 2.3 Quad4 HO or Ecotec but it's what came in my car and I want to see just how much hp/tq I can make with it. Since so many parts are interchangable between the two engines I may use the timing setup from the 2.3 HO and modify my front cover as needed to make it fit. Also the main reason for changing the oiling system for me is reliability, the 2.3 oilpump will make my engine much more reliable and allow me to remove the balance shafts, which eat hp/tq. I doubt in a daily driver that I will have many chances to rev the motor to 7400 rpms but it'll be nice to know that I can if I want. Plus in order to make 500 hp I need the airflow of the 086 head and we both know that's the limiting factor to high hp with the 2.4. I just want to beat the ricers at there own game, many people local to me scoff at my car and call it girly or booty and I'm going to shut them up permenantly when I get done.
2000 Z24 5spd header & catback for now.
To be technical, you would be trading about .13 liters...
Jrobz23 wrote:
ok I'll trade my .1L for...better bore/stroke ratio for real POWER (not low end tq which is useless FWD IMHO)...
Well, then the answer is simple... every FWD car modder should swap a k20 in it.
The only agruments I agree with you on are the stroke and the race block. Everything can either be custom made or made to fit. A shorter stroke with longer rods is definately safer to rev than a longer stroke with shorter rods. As for the race block, I don't know where they still sell the race blocks for the quads, except Mantapart......so my statement remains: I don't know where they still sell the quad 4 race blocks.
Brian Whalen wrote:every FWD car modder should swap a k20 in it.
holy Mr. out of context man!
so you don't like the timing setup of the 2.3? or the oiling? or the cam gears? or the head? or the etc etc... My argument wasn't bashing the 2.4 but asking why people go through the effort to drill this, ground that, and leave lots of room for error when they can swap in what they wanted in the first place, spend much less money, and be better off? the motor is litterally bolt in these days. No more wiring the whole car for odb1 or anything like that.
btw I no longer want to draw this off topic. I was merely making a point that might help him and others save some green. If the goal is not HP/$ but showing that 2.4L got some balls then hell yah, amen brother! either way hes rockin it in a J.
Sven you totally quarterloafed your computer..
If you look at the price of the modification to put the 086 head on a 2.4 block and the 2.3 pump swap, you would have been better with the Ho. Or even with a 2.6 witch use what? everything from the Ho except the crank. Also, the kellogg crank and GTU block still go by once in a while on Ebay and I think Josh at TRS has 1 or 2.
What you guys need to understand, people say the 2.3 is a dead horse but look at ALL the parts you can get compared to the 2.4. Olds build the 2.3 for RACING while the 2.4 is for CRUISING.
Gilles
2.3 Ho
Mfk-223 wrote:If you look at the price of the modification to put the 086 head on a 2.4 block and the 2.3 pump swap, you would have been better with the Ho. Or even with a 2.6 witch use what? everything from the Ho except the crank. Also, the kellogg crank and GTU block still go by once in a while on Ebay and I think Josh at TRS has 1 or 2.
What you guys need to understand, people say the 2.3 is a dead horse but look at ALL the parts you can get compared to the 2.4. Olds build the 2.3 for RACING while the 2.4 is for CRUISING.
and LD9 rods, and LGO size pistions with rist pin location of a LD9.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
