I'm in the process of building a 382 for spray. Going to be 200 of the lline and prob another 100 as soon as it hooks. What should I expect? What kind of fuel am I going to need? I do not plan to exceed 10.6 compression. I could go less if need be. Tranny is a th400 and rear is a 9in. All supporting suspension is there, except a tubular k-member. I doubt that I will do a tubular k because I will drive the car some.

 

Fuel...wet or dry? Dedicated fuel system? What do you have now mods/fuel wise?

No need to lower compression, nitrous and compression are friends, unlike boost and compression.

I run a tubular K Member on my daily driver and racer, no issues. I put an average of 1,000miles/mo on it too.

What about tuning? Gears? Tires? Rollbar, rollcage?

Are you building the engine or having one built? Ring gaps need to be addressed as well piston used, longevity reasons go with a custom nitrous piston, lowering the ring lands to prevent breakage under extreme cylinder pressures.

 

Fuel system has to be upgraded. Stock injectors and pump at this point. I talked to Jon@TSP(I think) he said I should be ok with a 255lph and some 36lb injectors. I was planning on a 200(wet) nx nozzle off the line and a 100(dry) dave's halo on out. We are gonna tune it in, i may get jason@tsp to get me a baseline so I can break the motor in and just use that as my starting point. Gears are 3.50 in the 9in. Tires at this point are Mt 325 radials. I am not building the engine but I have someone local who has enough experience 25+ years with a good track record. What sort of custom specs should I shoot for with the pistons? I am convinced that a recessed ring land is necessary.

 

you may want a little extra piston to wall clearance to let the piston expand a little more. you engine builder can expound on this. as far as fuel requirements, how much total power do you plan on making?

 

Most likely 480ish rw on motor. 383 through a th400 and a 9in. With 300 on top of that.

 

Ok, you didnt mention a dedicated fuel system for the wet setup, so I will say your going to run it on the edge by pulling fuel off the stock rail, and more so once you hit the dry side. You may end up running lean, very much so, on the drivers side bank pulling 200 shot of fuel off the rail. Just my two cents. You can combat this by either running a front mount FPR and return line, or a dedicated fuel cell. I'm not sure 36# injectors will do you justice on a 382 stroker with 100shot dry! I use 42# for my 347 and nitrous. I am not close to the 80%IDC so I feel comfy with these injectors. I would recommend 42's for your application. As for spec on parts, I tell the Cust. Serv./Tech guys what I want to do and let them get the right one I know the ring lands want to be lowered, Diamond has these, JE and anyone else...Looser ring gaps as well, but shouldnt need more Piston to Cyl clearance, just the rings at your point...now if you were wanting to go much larger maybe so.

 

I can do whatever it takes as far as a fuel system. I do not wish to run a fuel cell, besides that I am up for whatever it takes to make this safe. I do not want to spend all this money and chunk a forged motor because I ran out of fuel. So back to you CAT3, what do I need?

 

Well since fuel cell is out of the picture for you, I would say do a set of rails with a rail/front mounted Adj. Fuel Press. Regulator. You should be able to run a cell up front, with a low fuel light plumbed in, preventing low fuel activation is simple with an FPSS hooked to the fuel line from the cell also, so no worry on running out of fuel. Yes, I would really recommend a cell. Larger injectors, pump, rails w/ a FPR and return if no on the cell.

 

I'm setting up a similar system only i'm using a 250 out the hole with a 150 shot plate system on a time delay (FAST XFI) or if track conditions permit and if my ***** are willing to hang low enough out of my firesuit i'll jet the direct port for 300hp and the plate to 100hp....

GO WITH A STANDALONE fuel cell up front. Nitro daves sells them complete for like 600 bucks with everything. Cheap considering what a serious nitrous motor runs nowadays... I'm running a custom JE piston with a 300 top ring land (meaning .300 inch from the top of the piston to the first ring land...) plenty strong and designed for pro mods spraying kits as big as 500hp.... I haven't decided how i want to fuel my plate system yet. the big shot WILL be connected to the cell.... I have enough pump and lines (10AN) that if I split the line i could run it wet but i think i'm going to run the plate dry and use the XFI to enrich the fuel map thru the injectors when the plate kicks in..... your pistons should look like this....

 

Outlaw, are you getting your slugs coated? And they look like they are gas ported? I had mine coated since I had plenty of time from ordering them to redeploying from Afghanistan. Ceramic on top and oil shedding on the sides....next time the heads are off I need to take some pics.

 

.300 down top ring land, <(forged or billet piston). Bore .001 extra over the recommended piston to wall clearance and a top ring gap of .028 top ring a .029 second ring. <(4.00" bore engine) Max timing of 22/24 degrees under full spray and a decated fuel system... JMHO.

 

Question: Would you still use a +.001 on a billet piston built for the nitrous? My impression was, gas ported, reduced ring land piston built for juice didnt require the extra clearance because the swelling is reduced from the porting and thickness of the piston itself? Just asking, I dont build engine, I just make them quicker (as stolen from BASF).

Charlie

 

Clearance is your friend on nitrous engines. Look at it this way. How many posts have you read about guys saying> "My car has 75,000 miles on it and I spray the snoot outta it."...Stuff like that. Now I know that doesn't have anything to do with your billet piston question but the same thing applies. I put clearance in my nitrous engine... all of them, billet, forged, cast... and I've never had a problem. The last big nitrous engine I built had a blower, a 225 HP plate and a 300 HP plate running 13lbs of boost and I drove this car on the street and to the drags... 108 miles, "one way".... And I had .008" piston clearance on a 4.00" bore... Like I said...clearance in your friend on big nitrous kits.

JMHO

 

yeah they are gas ported and we're having the tops coated. gas porting helps a ton... also i have the reduction grooves in the top ring.... every groove is worth supposedly about 1 hp..... makes a diff with 8 pistons