So, I'm rebuilding my 420a, and I'm planning on (in the future) doing a turbo conversion as well as nitrous (100shot) What compression should I go for with the pistons if I plan to have both?

Search and the answer shall find you grasshoppa

Pretty much whatever you want. LOL. I'd go 8.8:1

What are your mods going to be?

intake
2.5" cat back
safc
aem Cam gears
udp
je pistons
eagle rods
upgraded fuel system (duh)
hi-flo cat
headers (till turbo time)
ported throttle body
stronger springs/lifters
california raisin on the dash :)

Originally posted by Graph-X
intake 2.5" cat back safc aem Cam gears udp je pistons eagle rods upgraded fuel system (duh) hi-flo cat headers (till turbo time) ported throttle body stronger springs/lifters california raisin on the dash :)

what are you gonna use that safc and cam gears for on an N/A car?? Paper weights :P

Please direct your attention to the first post I plan on having nitrous AND turbo. Thank you.

Okay.

Planning is a good thing. But they are totally useless until you have your "TURBO"


Your could probably find a turbo & manifold for the price of an SAFC and cam gears

I will still need them for the turbo. Let me now direct you to your previous post. You asked what mods I was going to do. That would include all the mods after the turbo conversion. It's obvious that your input on the original intent of the thread is done with... Thank you.

8.8 1 or 8.5 i would say . anything really thats lower than stock compression

Originally posted by Graph-X
I will still need them for the turbo. Let me now direct you to your previous post. You asked what mods I was going to do. That would include all the mods after the turbo conversion. It's obvious that your input on the original intent of the thread is done with... Thank you.

:P Very nicely done.

Ok here is the point that hasnt been discussed. You are planning turbo and N02. Now i am not sure what time frame you are going to be workign with but obviously lower compression is more of a benefit for forced induction. The problem is, if you rebuild your motor now with lets say 8.8:1 pistons, your car will be noticably lacking HP until you do build a turbo kit. A few members have slipped into this hole. A year later finances are not as plentiful and they are still trying to build/buy their turbo kits.

My advise for what it is worth is to buy the turbo kit now as long as your motor has good compression and no problems. Keep the boost under 8psi with a good fuel system. upgrade the motor later since it is the cheaper of the 2 options.

In the mean time that will give you a lot of time to research and find the best fuel solution for you. you will find the SAFC is not the best solution, even though it does work. The SAFC if relied on to make 500cc or larger injectors work will begin to alter your timing advance. This is mostly due to the ECU relying on MAP sensor readings to determine the timing advance.


If you search you will find a great deal of info on this. Also take some tiem to look around the main page in the MODS,TECH & MORE link. There is a section on building fuel systems that has a great deal of info regarding the AFC and other options. The SAFC is geared more towards the GST/GSX. If you look in the documentation the SAFC is not compatible with our cars, that is for a reason. Just because it works doesnt mean there arent very negative side effects. The SAFC can only be used to fine tune on our cars.


Terry

I did search the forum before posting. I also found the wonderful wealth of knowledge on the main page. I have everything printed out for the rebuild and the turbo conversion which will be the first thing I do after the rebuild. I am getting the engine internals and the cam gears and putting them on during the rebuild since I would no like to have to go back and tinker with it after I drop it in the car. Most of what I found in the forums pertained specifically to turbo. I know that nitrous would be high compression turbo is low compression. Would just under stock be a happy medium?

Well stock is 9.0:1, your next CR down is going to be what everyone runs. So your options are kinda limited in a way. Go with 8.8:1 JE pistons and turbo it right after as you said. Since you plan on running no2 and turbo right away together I would consider looking into the Megasquirt. Timing control is going to be important to run high boost. now if you want the no2 available to aid in spool up only and to maintain your turbo rpm's in between shifts then you are talking a little bit differently. In that situation timing control would not be too critical.

If you are interested in another compression ratio, look into Venolia Pistons. Exile Racing is ran by couple members here that can order any spec piston you want for just under 600.00 I think. If you are not familier with Venolia Pistons, John Force ran them religeously for many years. They are a quality piston.

I honestly cant stress enough with your plans to look into somethng more secure than the SAFC.

Terry

Thank you Terry for the constructive advie. I was under the assumption that stock compression was higher. What if I kept it at stock would this cause problems? I never thought about using the nitrous to keep the turbo spooled, I wouldn't use the 100shot to do that though... That's like using a grenade on an ant hill. What would you suggest instead of the SAFC?

Originally posted by Graph-X
Thank you Terry for the constructive advie. I was under the assumption that stock compression was higher. What if I kept it at stock would this cause problems? I never thought about using the nitrous to keep the turbo spooled, I wouldn't use the 100shot to do that though... That's like using a grenade on an ant hill. What would you suggest instead of the SAFC?

Well we discussed the MS and 8 injector setup so you can look into those. As far as the nitrous.....not a granade..lol Its actually very common to use nitrous for extremely large turbos. Hahn is a perfect example of that. As for using the nitrous as a power adder, consider spendign the 350 for the kit in your fuel management system and turning up the boost for the same effect.

If you want to consider stock compression with forged pistons then you would def want to have some sort of control over your timing. When you raise your boost levels towards 15psi and higher, you will def need to keep an eye on the tunign and timing.

Another thing to consider is a wideband O2 sensor. Look into Zietronix, tech edge, or the AEM uego. All will do the job needed.

Terry

Thanks again terry, you already know my boost goals which aren't super big, I think I will hit you up on the MS. I'll keep you updated on my progress with the rebuild and the turbo conversion.

Stock compression is 9.6:1 BTW

Actually Blair is right, not sure why i was thinking 9.0. Sorry

Yea and I agree with Terry. I would forget about the Nitrous unless you just want to be able to do that little purge psshhh i got NOS woooOt kinda thing

The turbo running "Efficiently" at said psi will be more reliable and perfom just as well as that extra nitrous. I'd save the nitrous for when you can't get anything more out of your turbo :thumbsup

Get the Megasquirt standalone, learn to tune your car and you'll be so happy it's not even funny. Then with the MS you don't need the safc to pull fuel or whatever. You tell it how big your injectors are, set cold start-up enrichments/idle/low boost maps. You can then go ahead and test and find out whats going on with the timing. If you log it and see it pulling the timing back you can say "Hey, fuck you" and tell it when you want the spark to fire.

Oh such a joyous thing.

How did you know that I had the purge kit? I bet you knew that I had the leds for it and the huge tach facing the passenger side seat. Oh, and I'm gonna get the biggest BOV I can find and have it blow out the wheel wells and go PSSSHH when I shift I'm also planning on getting the naws two big bottles!!