i didnt see this in the FAQ's and i couldnt find a search (maybe my search was off) but recently i was told that getting ported heads for a boosted engine is not good..then i asked a couple guys i know that know about cars and they couldnt tell me cuz they are v8 guys and dont know that much about 4cyl...so the question is.. if i get a S/C and forged pistons and rods with the 9:1 CR naturally i would want to up the boost, but that would cause me to blow the stock heads....so help?
...are you trolls that dumb that you cant realize mid 15s is slower then 14s?
Far as I know, it's a definite improvement for boost apps. I do know that since it's forced induction, the head doesn't need to be perfectly polished since the air is being forced through it anyways. I'd polish it as best as possible though, just to get the most out of it!
Failure is not failure if you learn from it
Only thing ive heard of is the port velocity problem with the GM superchargers, basic concept as i understand it is if you flow too much, the charger cant put out enough. Im turbo, so i dont know about that, all i know is on our engines, well at least the 2200, the head is the most restrictive spot, so it stands to reason that a good port job will help a lot.
Only a few people on these forums can give you the right answer to that question.
Anybody can f*ck up a head and make it flow like junk... and when you port a head for different applications a lot of things have to be taken into consideration.
Improvement? Yes. But it all depends on how its done, who does it, and what will be mated to it to help it work properly.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
wow your buddys who think they know stuff about cars obviously dont... it doesnt matter if its 3cyl or 12cyl..... the general idea is the same for any combustion engine... so i would question their knowledge about any car stuff
the more air you can get into your cylinders the better for any engine really but even more so with a boosted engine, you will see a drop in your PSI, but still will have more power with less boost which is a good thing... now with a s/c'er i dont know if you want to lower your compression ratio.... as some set ups on different cars, this is what would want to do but the supercharger kits for our cars dont give you enough boost to warent lower compression pistons (unless of coarse you are adding like a 75shot of nitrous or somthing like that)... you will not blow your head from getting it ported... but you will loose power if done improperly...now if you were talking about getting your cylinders bored out with high levels of boost this is where it gets risky with thinner walls and boost but there is probably only a hand full of people maybe not even that on this site who are boosting high enough for this to be a problem... but thats a hole nother topic
if you get a S/c'er for your Jbody... i would personaly not waist your time with internals... only thing i can see being worht the money would be port & polished heads... i ran my GM s/c'er probably to its limits on a stock bottom end for alittle less then a year (before i added the turbo into the mix) and i would get about 9-10psi of boost with alcohol injection and it was fine... im sure the ported head would have helped out some too as i know a guy who put the 2.3L head on his 2.4L Gm s/c'ed car and liked the difference...
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
Quote:
the more air you can get into your cylinders the better for any engine really
Well on n/a cars, it's not always the case...if you have a big port job and stock or mild camshafts, it's not building up enough velocity into the cylinder head.
Bust as far as booted applications, you are correct
www.kronosperformance.com / 732-742-8837
yea on N/A engines its only good to a point... i didnt put it as i know most people know that... but you will still get some benifits even on a N/A engine with getting more air into the cyl.... just cant go as buck wilded as you can on a boosted car...
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
wow thanx...that helps answer my question...but Josh you kinda brought up another question. I see exactly what ur saying with the thinner walls...but the piston set that i saw being sold lowers compression to 9:1, and its only .02 bore..now ill admit i dont konw a whole lot about engines, that is why im asking, but .02 isnt all that much is it? and how much boost can you actually get out of the GM s/c and if i didnt do the piston swap should i still change the cams? See i heard that our stock internals aint all that great... and plus with mine having about 77K miles and i know most of them were up in the 4K rpm + range b4 i got the car, i would be a little afraid of running boost on them. So basically what should i do as far as internals with the s/c?
o and one more thing about the heads.... all yall's response is based on the stock valves right? cuz porting would be widening the oppening and that would mean i need bigger valves right?
...are you trolls that dumb that you cant realize mid 15s is slower then 14s?
Rob Silvera wrote:wow thanx...that helps answer my question...but Josh you kinda brought up another question. I see exactly what ur saying with the thinner walls...but the piston set that i saw being sold lowers compression to 9:1, and its only .02 bore..now ill admit i dont konw a whole lot about engines, that is why im asking, but .02 isnt all that much is it? and how much boost can you actually get out of the GM s/c and if i didnt do the piston swap should i still change the cams? See i heard that our stock internals aint all that great... and plus with mine having about 77K miles and i know most of them were up in the 4K rpm + range b4 i got the car, i would be a little afraid of running boost on them. So basically what should i do as far as internals with the s/c?
o and one more thing about the heads.... all yall's response is based on the stock valves right? cuz porting would be widening the oppening and that would mean i need bigger valves right?
.020 overbore isn't that much but you still have to bore the cylinder walls to fit the wider piston. I think the pulley that GM gives you initially is like 5 psi, Josh can verify that cause I really can't remember.
You can go either forged route or stay with the stock internals. As long as you took care of your vehicle before hand and you're tuned correctly, you should be fine.
You don't have to change your cams if you don't want to.
www.kronosperformance.com / 732-742-8837
to correct you adam your wrong with the stock boost of the gm supercharger..... factory it was set for 4.5 psi but factors do play a role on how much boost it will acutally build on the stock 2.8 pulley. with real dense air like during the winter i wouldnt doubt you would see 6 psi. but in the heat of the day during the summer u may see nothin more then 4 psi.
another thing it really doesnt matter what your motor has been thru. I take my motor to redline just about every time i drive my car. still runs great and havent had a problem out of it yet. ive put about 10k miles on it and since ive done the first oil change ive ran mobile 1 synthetic 5w 30 oil in it. Just do some testing on your motor and do basic maintaince. yea it matters to a point on what it goes thru but if maintained and fixed to run properly the motor should out last the car its self in my belief.
the only thing that the 2.4s are know for is the oil pump being the weakest point of the car. but everyone that goes big boost with the gm charger has done 10psi which is the limit with that. of course you have to do supporting mods for it to work properly like fuel adjustments i believe, alcohol injection, and the proper pulley to to make that kind of boost.
just another note for you rob if your concerned about your motor. do like i said do a compression test to see what condition the motor is in. you could also have your oil tested to see if its getting other fluids mixed in with it. then after you get all your information you can go from there. then i would recommend you get some gauges to monitor your motor better when you go boosted this way if something goes wrong you can stop before some major damage can be done. simple gauges like oil pressure, water temp if you want but you should have a stock one.... but dont trust it fully there not completely accurate.
http://www.cardomain.com/ride/827643
boost will be soon for me....
Z Speed Cavi wrote:to correct you adam your wrong with the stock boost of the gm supercharger..... factory it was set for 4.5 psi but factors do play a role on how much boost it will acutally build on the stock 2.8 pulley. with real dense air like during the winter i wouldnt doubt you would see 6 psi. but in the heat of the day during the summer u may see nothin more then 4 psi.
another thing it really doesnt matter what your motor has been thru. I take my motor to redline just about every time i drive my car. still runs great and havent had a problem out of it yet. ive put about 10k miles on it and since ive done the first oil change ive ran mobile 1 synthetic 5w 30 oil in it. Just do some testing on your motor and do basic maintaince. yea it matters to a point on what it goes thru but if maintained and fixed to run properly the motor should out last the car its self in my belief.
the only thing that the 2.4s are know for is the oil pump being the weakest point of the car. but everyone that goes big boost with the gm charger has done 10psi which is the limit with that. of course you have to do supporting mods for it to work properly like fuel adjustments i believe, alcohol injection, and the proper pulley to to make that kind of boost.
just another note for you rob if your concerned about your motor. do like i said do a compression test to see what condition the motor is in. you could also have your oil tested to see if its getting other fluids mixed in with it. then after you get all your information you can go from there. then i would recommend you get some gauges to monitor your motor better when you go boosted this way if something goes wrong you can stop before some major damage can be done. simple gauges like oil pressure, water temp if you want but you should have a stock one.... but dont trust it fully there not completely accurate.
Thanks for the correction...I wanted to say 4 psi but I really wasn't sure.
www.kronosperformance.com / 732-742-8837
The GM s/c'er is all over the place as far as PSI for each pulley... its all dependant on temps out side MAINLY!! and then altitude and what not.... and the GM s/c'er is VERY picky about this... as there is a wide range of psi being achived from every one on the stock 2.8" pulley
now the supercharger will only get you 9-10psi MAX!! and thats with alcohol injection and spining it past its suggested RPM but you can still do it you just need to change the oil in it sooner on the s/c'er but thats still like 50,000+miles (if not more) so its not that bad.... but the Roots blowers are VERY unstable at the speeds that a 2.6" pulley spins it at so you will see boost spikes with alcohol injetion ( i know i did)..... i would NOT put lower compression pistons in with this S/c'er kit... if any thing go slightly higher to say 9.5:1 or 10:1 compression.... (just make sure you got a knock gauge and Wide band if you do and im sure you would be fine)
and as for the small bore.. with the GM s/c'er you will never make enough boost to even worrie about the walls being thiner.... even with a small shot of nitrouse on top of the s/c'er.... so i would say thats all up to you if you want or not...
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
Josh F wrote:
if you get a S/c'er for your Jbody... i would personaly not waist your time with internals.
hey now, i did my internals but im also running nitrous with the charger
ok...i really appreciate the help guys... i honestly dont know all that much about s/c's so i am still researching and learning. Do any of you know about the Vortech s/c? ive seen it for sale on several websites, but i know its a centrifugal (sp) not a roots. meaning that it doesnt run off a pully right? so that would make it pretty much a turbo.. maybe im completely wrong... but what would you guys say if i asked all the same questions if i decided to go with that s/c?
and another side question... about what 1/4 mile time and hp ratings would i get from runnin about 8-10 psi of the GM s/c?
...are you trolls that dumb that you cant realize mid 15s is slower then 14s?
BOOSTED wrote:Josh F wrote:
if you get a S/c'er for your Jbody... i would personaly not waist your time with internals.
hey now, i did my internals but im also running nitrous with the charger
ahah yea your a special case ahaah... but yea with nitrous then yes internals...
Rob DO NOT!!!!! go with the RSM s/c'er kit... 1 you wont get as much power and 2. you will not have as good of a tune/reliablity as the GM one... i have personally seen the GM s/c on a cavy walk all over a RSM s/c'ed sunfire time and time again.... dont do it...
either go with the GM s/c'er or turbo....
and yea the Vortech's are just a turbo with a belt driven turbine....
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
