Alright guys im back with the 420a after the rotary and the 4g63 lol. Im looking to stay N/A and run a small shot of nitrous. This isnt my first all day rodeo with these cars either. I want to stay as reliable as possible. What i have for my question is compression and the size of shot i can do? From what i know leaving the motor completley stock is the best way, but im on here so you know its not staying stock lol. I know you can mill the head and take out the middle layer of the mls head gasket to increase compression and still be reliable. Now what else can i do to the head to gain more power and still stay reliable, this car gets driven every single day now. Is there any higher compression valves of some sort? I have ran a 75 shot on my last 420a but it was rebuilt and im thinking of only doing a 50 shot for reliablity reasons. If you know of any other things like swapping pt parts or something else let me know.

Mods on the list for now. Feel free to add if you think.

CAI
Header
Test Pipe
2.5 Exhaust
Cut Out
UDP
Walbro 255 w/rewire kit
Venom intake manifold
60mm TB
Adj Cam Gears

Are you planning on rebuilding the motor?

No i dont plan on rebuilding it at all untill it blows. Then when it blows im just going to do stock rebuild. From my understanding the more you dont mess with internally the more safer and reliable it is. Ohh arp rod bolts but thats it.

No need for the 255 fuel pump. You may be able to get away with the stock pump but if you cant then get a 190 so it wont overrun your stock FPR. And I disagree about a built motor being less reliable than a stock one. When you blow your motor you would be dumb to rebuild it stock if you plan on running No2. Then you would have a strong motor that could take a much bigger shot of gas and still be fine.

Originally posted by SilvrEclips
No need for the 255 fuel pump. You may be able to get away with the stock pump but if you cant then get a 190 so it wont overrun your stock FPR. And I disagree about a built motor being less reliable than a stock one. When you blow your motor you would be dumb to rebuild it stock if you plan on running No2. Then you would have a strong motor that could take a much bigger shot of gas and still be fine.

+1..good ideas with fuel pump

Yeah your right i forgot about that with the fuel pump burning out the fpr. But i dont want to spend the money on forged pistons and rods its just a daily driven street car. I dont think there is a need to spend that much more money to build it then run 100 shot i dont think it would be worth it. But thats my own two sense lol. And after all it is my car im just asking for advice and opinions.

Originally posted by SilvrEclips
No need for the 255 fuel pump. You may be able to get away with the stock pump...

I run my NX 75 shot with stock fuel pump without any problems. No drop in fuel pressure when spraying.

Running a bigger fuel pump wont make our regulators shit out. You can get away with a stock fuel pump and a rewire spraying a 75 shot. Honestly a 50 was weak when I sprayed it, I would deff spray at least a 75 with a bottle heater and all the other safety precautions that nitrous brings. So to stay reliable in a nut shell:
Intake

Exhaust

Header

UDP

MP60mm tb or Jeep 60mm

At LEAST rewire your stock fuel pump

crane 12's or 16's(I would go 16's)

If you go with 16's then upgrade valve springs

2.4L lifters and rockers

Wet nitrous kit with bottle heater and blow down tube and fuel pressure safety cut off switch

Fuel PSI gauge

WB02

EGT

Oil PSI

That should get you a fun daily that is pretty damn reliable. Then if you want to build the motor some more get forged pistons and rods and go from there.

I wouldn't even want to have to worry about blowing it. Just rebuild it or pick up another block for a few hundred and rebuild it and swap it. Just my way of thinking. I don't know why people have to wait til they blow it up to rebuild it. :shrug

Originally posted by halfasss101
I wouldn't even want to have to worry about blowing it. Just rebuild it or pick up another block for a few hundred and rebuild it and swap it. Just my way of thinking. I don't know why people have to wait til they blow it up to rebuild it. :shrug

I'm with you on this one. I would build a low compression block with forged internals, and some light headwork. That way you could spray damn near as much as you wanted and still have the option to go turbo without tearing your motor down again.

Originally posted by ThePerfectShift

Originally posted by halfasss101 I wouldn't even want to have to worry about blowing it. Just rebuild it or pick up another block for a few hundred and rebuild it and swap it. Just my way of thinking. I don't know why people have to wait til they blow it up to rebuild it. :shrug

I'm with you on this one. I would build a low compression block with forged internals, and some light headwork. That way you could spray damn near as much as you wanted and still have the option to go turbo without tearing your motor down again.

Low compressions sucks dick. Lowering compression is the old school way of building a block and having a large window of tuning forgiveness. With how cheap MSnS is today and if you can find a SFMU why not build it with at least stock compression or higher. I ran low comp and didn't like it. Throttle responce sucks. As far as rebuilding it...I agree. Just get a spare block build it and when its time to put it in either sell the old and make some money or keep a good back up...

If he just wants to run a 75 shot. Then he should just rebuild it stock as long as he doesn't spray it to and from work everyday. I would do a new OEM clutch too. Never know if its going to hold. I dont know how many times i've read posts saying they're only boosting 5 psi on stock clutch and it slips since its just too worn out. For the price, just go with like a stage one SBC. Then you have nothing else to worry about.

Well if your saying a 75 shot would still be as reliable then i would run that but the rule of thumb that i was told is whatever your motor makes you can sray half of that. 140 stock mine is probably 120 with the miles but with all of the parts added i guess a 75 would be ok. Oh no looking to buy the spec stage 2 clutch kit. I have skipped out on clutches before and it sucks to do all the work then take out the trans and replace the clutch. Im getting my parts list together when i get all the info i need and i have about 95% of it right now. Yeah im not going to run the 255 fuel pump but i will run the 190/fuel pump rewire, with a adj. FPR, (i know its not necessary). Anymore opinions would be greatly appreated or comments. The MORE THE BETTER.

Originally posted by RX73Rotorj
Alright guys im back with the 420a after the rotary and the 4g63 lol. Im looking to stay N/A and run a small shot of nitrous. This isnt my first all day rodeo with these cars either. I want to stay as reliable as possible. What i have for my question is compression and the size of shot i can do? From what i know leaving the motor completley stock is the best way, but im on here so you know its not staying stock lol. I know you can mill the head and take out the middle layer of the mls head gasket to increase compression and still be reliable. Now what else can i do to the head to gain more power and still stay reliable, this car gets driven every single day now. Is there any higher compression valves of some sort? I have ran a 75 shot on my last 420a but it was rebuilt and im thinking of only doing a 50 shot for reliablity reasons. If you know of any other things like swapping pt parts or something else let me know. Mods on the list for now. Feel free to add if you think. CAI Header Test Pipe 2.5 Exhaust Cut Out UDP Walbro 255 w/rewire kit Venom intake manifold 60mm TB Adj Cam Gears

This setup is similiar to what I am doing with my motor. I am rebuilding it with 10.5 compression and fully built bottom end. Reliability is also a huge factor for me. With a built bottom end, how much nitrous could I run and still stay relatively reliable?

This setup is similiar to what I am doing with my motor. I am rebuilding it with 10.5 compression and fully built bottom end. Reliability is also a huge factor for me. With a built bottom end, how much nitrous could I run and still stay relatively reliable?


I am not an expert with nitrous on high compression, but 150 shot sounds good to me. Possibly more but i couldn't tell you an exact number. You would be putting down some good power though with a 150 shot on 10.5:1 compression. Probably 250ish at the wheels i'm guessing. Maybe a little more. But i've never been much for nitrous. To me, Nitrous and reliability don't fit well in the same sentence. But if its tuned for it, thats another story. But who the hell tunes there car for nitrous these days? People just throw the bottle in there and push the button

Nitrous is as reliable on how much you push the button lol. Some can control some cant. Im getting mine tuned but im having trouble finding tuning for it. Megasquirt is expensive and so is the aem fuel ignition controller. I dont want to spend that much on tuning for just a bolt on car. But im still looking.

Originally posted by RX73Rotorj
Megasquirt is expensive and so is the aem fuel ignition controller. I dont want to spend that much on tuning for just a bolt on car. But im still looking.

You think the MS is expensive? You are not going to find anything that has the same abilities for cheaper.

Exactly, and I wouldn't use a push button style nitrous activation. I ran a electronic WOT switch. You can go even further and get a window switch that can also block out your gears so you don't spray in first but spray after 3k in second and from then on. The hardest thing that nitrous is on in an engine in my opinion is the rods because of the sudden impact of power. Now if you stay in the nitrous too long you can creat too much cylinder temps and melt a piston but you shouldn't need to worry about that too much unless your being stupid on the street.