lets talk natrually aspirated

[qnz]

I was under the impression that DOHC doesnt have huge gains in low HP N/A. I remember seeing dyno graphs somewhere of some hondas DOHC and SOHC with same everythign else and the SOHC made its power sooner and peak was the same.

[mrg7243]

but the DOHC has more aftermarket support, such as intake manifolds, different cam profiles, better springs and retainers.(for the galant )

And for the pistons not clearing the EVO head idk if they do, the kia pistons do have valve reliefs cut into them, but if you are worried about that, just have custom pistons made for the 4g64 with the 63 for higher compression

[Exhaust power]

I was under the impression that DOHC doesnt have huge gains in low HP N/A. I remember seeing dyno graphs somewhere of some hondas DOHC and SOHC with same everythign else and the SOHC made its power sooner and peak was the same.

Thats kind of weird i think that might come down to cam tuning. I would think the DOHC would have the larger power band since the cams could be tuned individually. With that said for a everyday car torque numbers make the big difference in thinking if your car is fast. So ill definitely be looking at torque numbers when tuning.

[Exhaust power]

but the DOHC has more aftermarket support, such as intake manifolds, different cam profiles, better springs and retainers.(for the galant )

And for the pistons not clearing the EVO head idk if they do, the kia pistons do have valve reliefs cut into them, but if you are worried about that, just have custom pistons made for the 4g64 with the 63 for higher compression

O im not concerned about it, i just dont see the reason to run a comp evo head.

[Stewi]

thats kind of weird i think that might come down to cam tuning. I would think the dohc would have the larger power band since the cams could be tuned individually. With that said for a everyday car torque numbers make the big difference in thinking if your car is fast. So ill definitely be looking at torque numbers when tuning.

exactly

Ideally with a DOHC setup your gonna want the largest valve possible and a cam profile that supports your power goals and drivability concerns.

If you build is really budget minded and looking to gain only about 80whp or so over stock. I would start doing some research on how much valve clearance exists on the stock 8g SOHC setup. The reason I ask is because if there is a good amount of valve clearance, nothing would stop you from removing the stock SOHC head, having some porting done and having the head milled down (the math here is going to be CRITICAL) which would increase the final compression, and even ordering a custom headgasket thats thinner than stock (again raising the final compression). With budget in mind custom head gaskets are cheap, probably about $75. By going this route, you save the money in buying parts associated with the DOHC swap, re-use your stock stuff (which you know is good if your motor is healthy) It will allow your money to be spent on the RPW cam, header and potentially a custom intake mani or ITB setup. Im sure you could get it tuned on an EVO ECU instead of a standalone (again, saving money)

[blue8g]

I was under the impression that DOHC doesnt have huge gains in low HP N/A. I remember seeing dyno graphs somewhere of some hondas DOHC and SOHC with same everythign else and the SOHC made its power sooner and peak was the same.

I've never seen an NA SOHC honda break like 170 hp
I've seen NA DOHC Honda's break 300 hp

[mysticj]

Comestic makes a .027" HG which will bump compression by 0.3cr. I wrote something awhile back that the 8G Galant had two different compression ratio: 99-00 had 9.5 while the Cali spec and 01-03 had 9.0cr.
You can't run big lift on the G4JS pistons, valve pockets too small plus the Evo head don't flow well without ported/polished for large lift.




I seen a NA DOHC 4G64 putting down about 170whp.

[Exhaust power]

exactly

Ideally with a DOHC setup your gonna want the largest valve possible and a cam profile that supports your power goals and drivability concerns.

If you build is really budget minded and looking to gain only about 80whp or so over stock. I would start doing some research on how much valve clearance exists on the stock 8g SOHC setup. The reason I ask is because if there is a good amount of valve clearance, nothing would stop you from removing the stock SOHC head, having some porting done and having the head milled down (the math here is going to be CRITICAL) which would increase the final compression, and even ordering a custom headgasket thats thinner than stock (again raising the final compression). With budget in mind custom head gaskets are cheap, probably about $75. By going this route, you save the money in buying parts associated with the DOHC swap, re-use your stock stuff (which you know is good if your motor is healthy) It will allow your money to be spent on the RPW cam, header and potentially a custom intake mani or ITB setup. Im sure you could get it tuned on an EVO ECU instead of a standalone (again, saving money)

milling the head is another option. But if the expenses out weigh the sonata pistons then it would be considered .this wont be done on my current engine since its my daily i would buy a jy engine and rebuild it .

What i can do is buy a 4G64 drop the G4JS pistons in get the head ported and drop it in the g like that. then ill just keep on tuning and upgrading on the go this will save me money in the short run instead of doing everything at once then i can get different dyno numbers at different stages i upgrade.

I can send my head off to my teacher(robert lauer) but im not sure what the price is on his head porting. I should just call him but i wouldn't pay no more then 300 . anyway hes a professional and builds panoz motors for lamons series back then.Tought me things i wouldnt ever find out about N/A building.

[Exhaust power]

Comestic makes a .027" HG which will bump compression by 0.3cr. I wrote something awhile back that the 8G Galant had two different compression ratio: 99-00 had 9.5 while the Cali spec and 01-03 had 9.0cr.
You can't run big lift on the G4JS pistons, valve pockets too small plus the Evo head don't flow well without ported/polished for large lift.




I seen a NA DOHC 4G64 putting down about 170whp.

good info.


Rpw makes different stage 2s that dont require valve springs/and retainers so i guess that would be mild enough to run with pistons . But technically there should be some numbers floating around on club 3g about the valve piston clearances to paint better details. I need to do more digging, cause right now im bouncing around from sohc to dohc and which would be the better set up. first i need to form a theory price list for both and start from there.

[Stewi]

plus the Evo head don't flow well without ported/polished for large lift.

I couldnt disagree with that more.

A stock unported, stock valve size EVO head has been tried and tested time and time again to make over 600whp on boosted applications, there is no reason it couldnt flow enough volume to support 300whp N/A. Granted the port and polish will help it a good bit, but its definetly not required.

[Prophet]

lol... I am glad to see that other members are interested in going the route Brandon went...

[duh2150]

I have a picture comparing the Dohc Kia head to the stock 8g I'll post it up I anyone wants to see it

[Exhaust power]

more pictures the better!

[WhiteGalant]

Think I might pick up a set of dc sports headers for the fun of it

[duh2150]

Kia at the bottom 8G at the top

some random Kia head pics




i wish i had more pics but i guess some got lost

[mrg7243]

yours is ported, how much though??

[Exhaust power]

Ok i did some research and didnt know stand-alones cost so much. As stewi said to go with a evo ecu, i was also thinking about the manual eclipse ecu. Now i remember SDP_FRK explaining into detail about remapping the the eclipse ecu and stuff of that sort. So is the eclipse ecu a possible option? because theres a couple at the jy for less then $50 bucks wich is friggen cheap compared to internet and i dont want to see how much a evos cost lol.

What to do for injectors or do i even need them? some where on tgc i read about the injectors and some one was talking about they max out 230 (whp-hp? idk). I dont really know too much about our injectors, but if some one could spread some light on this it would be very interesting to talk about. Im keeping in mind WRX injectors if i end up maxing out the 4g64's. Also Are the G4JS injectors the same as 4G64S?

Ok Spark/Ignition. To my knowledge I probably wont have to do any tunes ups on this system except for plugs or am i wrong? also does any body have any veiws on direct ignition? I read a while back that they arent anything advance, performance wise.

Ok heres my list for now i went a head and split parts up in stages to help keep down short time consumed money. The stages start with parts need 1ST and goes down till i reach basically luxury items.

Stage 1 (well needed)
G4JS DOHC/Pistons
blox 264/264 cams
adj cam gears
CAI
6G74 TB

Stage 2 (needed but drivable W/out in theory)
2.5 E/H
ECU (EVO maybe eclipse manual)
Tune

Stage 3 (may need, luxury, power)-the Tune will tell me what i need
wrx Inectors
Warmer Plugs
Evo I/M
fuel pump

Ill think of more if possible.

[mysticj]

Either the Eclipse, Evo, or Lancer ECU will do. The Evo is a tad expensive, the Lancer ECU become an Evo ECU when flashed. :)

I'll suggest adding these items to Stage 1: Evo IM, Blox 272/264

[Exhaust power]

Either the Eclipse, Evo, or Lancer ECU will do. The Evo is a tad expensive, the Lancer ECU become an Evo ECU when flashed. :)

I'll suggest adding these items to Stage 1: Evo IM, Blox 272/264

Sounds good for the ecu possibilities. I have the EVO IM in stage 3! lol . And
Running a more aggressive intake cam then exhaust? whats the benefit? And i believe ill need new springs to match the 272.

[qnz]

you can flash your stock ECU. no need for an evo ecu.