Considerations for a motor running N2O
 

Besides the regular machining and precuations for building a motor are there any other things I should consider for a motor that is going to be running nitrous?(and for those who don't understand nitrous I mean NAWZ!!!111)

I am planning to almost always use pump gas on this motor as it is my daily driver and I really don't feel like having to run and get race fuel just to have some fun on the freeway. And please hold the comments back on this one but I have no intentions on using any other size turbo than my current EVOIII16G. I know it may sound dumb, but I don't want one of those uber laggy popcan swallowing turbos that are found on the local 500 and up hp cars. Plus the motor is only a 2.0. I currently enjoy full spool by 3700 RPM, mainly thanks to a perfectly ported head(thanks mike!). I don't want to sacrifice that in the least. But I do want to break 400whp, hence the spray.

I will be running some less aggressive pistons compresssion ratio wise in order to run 20-22 psi on pump with the appropriate fuel mods. I really want to only build this motor once as I am not loaded financially. I have already picked the shop the shop that will build it(they don't know yet), and want to go there with everything in hand and a good idea of what needs to be done to block to hold up with my plans for it.

Shane had mentioned getting the block o-ringed(or something like that) in order to keep all that spray in the chambers. I am not really sure what this does as I am an internals noob. I will be running a 50 shot that may be upgraded to a 75 if I decide it is needed.

Are there anyother considerations I need to look at inorder to get the most out of this block? Any and all POSITIVE feedback is appreciated.

Thanks in advance,
Matt

a little off topic but 3700 rpms to get full spool seems slow for a 16g since my 20g got it by 4000. That was on a stock 2g head, tb and intake manifold.

um, guys.. my 50 trim gets full spool by 3900 and that was full 25psi.
on colder days i've seen full boost as early as 3600, my t28 spooled at 2900 full boost 18psi.. honestly, i think you should upgrade to 50 trim, whe ever had them was pretty happy with them..

-E

Yep, my PTE 50 trim got 23 psi by 3800 rpm. It really sounds like you need to just switch turbo's and not build the engine. 2.0's have made 430 whp on pump gas pretty easily with a 50 trim. I would definately go that route. Nash made 531 whp on stock internals, so you should be safe without building your engine too.

The head porting may slow spool a tad, but it shouldn't be much.

Well then maybe I have my number wrong, I was mainly looking at the torque spike on my dyno sheets and placing it there, does that sound right? I haven't driven it in a while so I am unsure exactly where it hits full spool. Hmmm... Maybe I will have to get it to run again just to see where spool is.

And the reason I am buiding a motor is because the current one is 177k old and every seal in that that is supposed to hold oil in, doesn't.

If I were to look at a 50trim I would probably look at a FPGreen as I am told that it is one of the fastest spooling 50trims out there.

Thanks for the input thus far.

Turbos spool slower on a dyno, thats why the number seems higher than usual. You probably don't have to O-ring it, if you aren't going for crazy high race gas boost numbers, plus nitrous on top of it. Just try to get a good seal on that headgasket. If you are just going to run an AFC, get a socketed EPROM ECU so that some changes can made to the top few rows of the stock timing map.

I assume you are going with a wet kit right? Direct port or single nozzle? You should be fine with a 50-75 shot on a stock motor assuming you have ARPs and a new HG. I knew a couple kids who ran a 75 shots on a 14bs perfectly fine.

Yeah, wet with a single nozzle. And I will definately be doing ARPs and a Cometic HG.

I agree with shane, for that level of boost/spray, I don't think the O-ring is necessary. Matt already has a socketed Eprom so he is good there. If you want, Matt, give me a call tomorrow, I have some ideas for you.

Cool, will do do doodely doo!

So does anyone know if DSMLink for 1g's will have a seperate NOS table and activation device like it does currently in the 2G version?

Does the 2G version of DSMLink have a N2O table? I thought it just had some activation stuff.

I can program that right into your eprom and save you alot of cash.

Shane, now that I look at it DSMlink for 2g's only has an activation section, not a seperate table.

Eric, if it turns out that the 1G version doesn't do it, I was going to ask you anyway. I am looking for something like DSMLink offers, but with also a seperate table that will activate when the nitrous is active, and the return to the normal table when it is deactivated.

If your talking nitrous control, the worst case senerio, if the eprom can't do anything is use the 2nd map on the s-afc for the nitrous tune. Im pretty sure he can pull timing via the eprom and an input or something.

Adding a second nitrous map would be difficult, for me, not impossible though.I don't know if this is what you are looking for but, a little while back, I was working on ECU nitrous control.Basically the A/C button arms the system.When armed and certain conditions are met (load,rpm,speed,TPS etc), the ECU will switch on the A/C output(now hooked to nitrous solenoids), fire the nitrous while retarding X amount of timing.The amount of timing pulled could be loosely based on load, maybe a few different retard values to go with a few different load points.

I would assume he was only looking for an on/off switch and pulling timing x-amount. But the extra fuel will be there so thats good.

~John

Have you ever ridden in a car with a "big" turbo? My 20g shows positive manifold pressure at 2100rpms, I cant say when it shows full spool because I am still only at 18psi for the clutch break in but it is hitting that 18psi by 3500rpms EASY and it wants to keep pulling far beyond redline, something a smaller turbo such as a 16g wont be able to do since it runs out of air at higher rpms, especially with mods as simple as a set of cams or ported head.

If you are wanting to run 20-22psi on the 16g on pump gas you would be severly limited in the cr you could run. A turbo that is larger and more efficient at that boost/airflow level could make more power without the risk of detonation even with higher cr and pump gas. Also remember that if you are choosing to run a "big" shot of nitrous with a small turbo vs a big turbo (because you choose to race from 1500rpms and dont want to wait for the turbo to spool or downshift) then the turbo is going to become a restriction in your exhaust and intake path...

My $.02

A 20G is not a big turbo they spool pretty fast, it has a little more flow capability than the EVO III 16G, but it still runs out of steam on the 2.0 at higher boost. The EVO III 16Gs are not nearly as small as the old regular 16G and "Big 16G". People are making around 400whp with the EVO III 16Gs. You were lucky to make 350whp with the old Big 16G. Getting over 425whp out of a 20G takes some work. He already has the EVO III 16G and doesn't want to spend money on something else, that is probably the major reason he is sticking with it.

Why are you running 18psi while breaking in a clutch? You are supposed to take it easy during clutch break-in and not boost the car at all.

The evoIII does not flow significantly more than its big or small cousins but I dont have the compressor maps handy to see exactly what they flow(the compressor wheel is ligher so it spools faster but doesn't flow that much more). I did compare them though at one time and IMO a anything less than a 20g is really a waste of money unless your stock turbo dies and you just need something to replace it. Like you said the 20g is not that large of a turbo so its perfectly streetable, they can be had for not that much money (got mine with 6 hours of run time on it for 450), it does require a fmic and injectors but can be run on the stock internals fine, and it has gone 10's. Granted most people wont be running 10's with thiers but there aren't many cars out there that will touch a properly tuned dsm with a 20g and you dont need to keep refilling a bottle to do it ;)

As for the clutch clutch wear is only occuring during engaugement/disengaugement so assuming your taking it easy on the shifts and not launching it you wont be causing any more wear on the clutch by boosting it once its in gear and moving unless one has enough torque to force the clutch to slip once the pedal is fully released and I highly doubt am making enough power to do that with an an act 2900. Also 18psi is about the lowest boost i can run with the external wg.