"Occasional" Nitrous 150-300HP...What do Engine Builders/Nitrous Racers do to prep a build?

[biomedtechguy]

You've raced before? Or is this just a jump-in with all 8 feet type deal. You'll be working harder than Lars Ulhrich on the skins

That put a BIG ****-eating grin on my face.
I've never run 11s. Got less than 2/10ths away on my V-Rod...
My buddy hasn't raced, a lot, but I have to admit he's had a little more experience than I have over the last 40+ years, since we were teenagers, but we've always been "into it" and my first 1320 trip was at 16 in 1978. He just ran 9.8 at 139 in his 2005 supercharged Vette.
Look, I posted this thread in the Racers forum because while y'all are KIND enough to reply without cruelty, I am hearing you! I just figured having a little "something extra" that I could reach for, if it looks like I'm close but still 1/2 car behind at the ⅛ mile or 1K foot mark, a 125-150 shot wouldn't be something that set up properly would cause any trouble, but could turn a close L into a close W.
We're talking about being in 3rd or 4th gear by the time I hit the juice.

 

[biomedtechguy]

I'm probably going to go to a dual disc clutch and pressure plate system since I'm having the throwout bearing replaced with a Hydramax TO bearing, and the HitMaster launch control system installed. I'm thinking (and getting some info from those who have dual disc) that would be better to handle the friction that the HitMaster will impart.
I've got some calls to make.

Well I spoke with Grant, the man behind the ClutchTamer and HitMaster and said if he thought I would see a big advantage or moreso-a necessity-to switch from my 2,950 pound McLeod diaphragm style PP and organic disc to a McLeod "800 HP" dual disc clutch system, NOW would be a good time since the transmission is out to replace the throwout bearing with my new Hydramax unit. After discussing this, I'm going to give what I have a shot. To be clear, if anything, I AM the one who was ready to make the switch, but Grant convinced me that my current setup isn't doomed to a short, horribly mangled and glazed demise...So the PP and disc I have is paid for, and served me well for several years, so what the heck. If I find my launches produce a smell like a chicken coup caught fire in a wig factory and a tractor trailer locked up its brakes for a couple of miles, I guess I'll go to the dual disc then...

 

[RemCharger]

4bbl auto. with your drive I could see it work! put the 6pak/stick back in later!

 

[RemCharger]

But the point of your question about nitrous ring gap; no, it wont burn any extra oil.

 

[vintage chromoly]

While the car is apart, you may want to consider an SFI bellhousing. Maybe I missed that you already have one, or are installing one.

 

[biomedtechguy]

While the car is apart, you may want to consider an SFI bellhousing. Maybe I missed that you already have one, or are installing one.

That will happen when the new motor goes in.

 

[QuickBpBp]

And that 9 sec clutch car I don't believe weighted 3900#? Looked more like 2900#? I wouldn't screw with nitrous on a big motor. To get 150-250 more horse from a big cube motor is quite a shot. It's better to build for it. JMO. besides, you have to then mess with ignition timing. Typically retarded to give valve timing a chance to catch up. And guess what that means? Runs choppy at idle. If you have a true solid N/A 800+ horse? Be happy you don't kill yourself at WOT. Because it will find a weak part and kill that.

They have controllers to do this so no need to have timing set-up for a "Nitrous only pass"... I had a timing retard box on mine activated by a switch when the nitrous was powered... No concerns..

 

[biomedtechguy]

I had a timing retard box on mine activated by a switch when the nitrous was powered

I just asked another forum friend about that, supposing that such a device existed. Throttle actuated microswitch closes, timing retards, outboard carburetor lean spike passes, nitrous and extra fuel enter...all within about 1.1 seconds...
OR when you say "nitrous was powered" do you mean arming the system (powering it on)?

 

[Hemirunner]

I just asked another forum friend about that, supposing that such a device existed. Throttle actuated microswitch closes, timing retards, outboard carburetor lean spike passes, nitrous and extra fuel enter...all within about 1.1 seconds...
OR when you say "nitrous was powered" do you mean arming the system (powering it on)?

Most modern ignition systems have provisions for this. Once you change engines, I’d recommend going to the MSD ignition and get something with built in retard capability. The 7531 is excellent for multiple gear/nitrous retards and they’re stackable. It’s light years beyond the prehistoric orange/chrome/gold box junk.

 

[biomedtechguy]

Most modern ignition systems have provisions for this. Once you change engines, I’d recommend going to the MSD ignition and get something with built in retard capability. The 7531 is excellent for multiple gear/nitrous retards and they’re stackable. It’s light years beyond the prehistoric orange/chrome/gold box junk.

I have started threads about and posted about: "Fully programmable ignition settings systems for carburetors" as part of my QUEST for the BEST ignition system.
I've even seen a "homemade" setup that allowed for all parameters to be preset on a laptop.
I have the FBO system right now, but I have my eye on another one that allows for user "tune maps", and I'll post about it when I learn more.

 

[Hemirunner]

I have started threads about and posted about: "Fully programmable ignition settings systems for carburetors" as part of my QUEST for the BEST ignition system.
I've even seen a "homemade" setup that allowed for all parameters to be preset on a laptop.
I have the FBO system right now, but I have my eye on another one that allows for user "tune maps", and I'll post about it when I learn more.

The MSD 7531 uses a laptop to program ignition maps and also has limited data logging capability if you wanted to run a map sensor for manifold pressure it’ll log that. You can also run it in the crank case and it’ll let you know when you rattle the rings because the tune is off.

 

[Hemirunner]

I just asked another forum friend about that, supposing that such a device existed. Throttle actuated microswitch closes, timing retards, outboard carburetor lean spike passes, nitrous and extra fuel enter...all within about 1.1 seconds...
OR when you say "nitrous was powered" do you mean arming the system (powering it on)?

Fix the lean spike with additional accelerator enrichment. Lean is mean right up until nitrous is involved and then it’s a cutting torch lol.

 

[440rb]

Lean is not what kills pistons and motors if you have enough timing out with N20, its too much timing on bigger shots, just the same as being too rich will lift ring lands....Its all engine combo efficiency dependent to start with is how I learnt it. Too much timing and your fighting the increasing CP too early and defeating what your trying to do in the first place.

 

[biomedtechguy]

Fix the lean spike with additional accelerator enrichment.

No accelerator pumps on the outboard 2bbl carbs. Lasts less than but about 1 second on tip in. Vacuum outboard carbs.
The guy I bought the Weiand intake from:

he has "supposedly" NOS mechanical 3x500 CFM 6bbl setup, and while I may be able to "get a deal", honestly if I make a change I'd rather just go all in and get the F&B direct port injection 3x2 EFI setup:

 

[Hemirunner]

No accelerator pumps on the outboard 2bbl carbs. Lasts less than but about 1 second on tip in. Vacuum outboard carbs.
The guy I bought the Weiand intake from: View attachment 964359 View attachment 964360
he has "supposedly" NOS mechanical 3x500 CFM 6bbl setup, and while I may be able to "get a deal", honestly if I make a change I'd rather just go all in and get the F&B direct port injection 3x2 EFI setup:
View attachment 964361 View attachment 964362

Figure out your EFI plan now as the Holley HP can control both ignition and fuel eliminating buying both and adding to both the cost and complexity.

 

[biomedtechguy]

Figure out your EFI plan now as the Holley HP can control both ignition and fuel eliminating buying both and adding to both the cost and complexity.

Thanks! I will keep the FBO for now.
Since I have put the deposit on the aluminum block, at least I have that first step taken. I don't know how long it will be until a complete engine is under hood. If I have it in the car by October 2021, I will consider that a win.
As far as EFI plan, you see it in those pix. F&B 3x2 EFI DPI and whatever control system I can get support on, that Bruce at F&B and maybe my builder can agree on.
I just don't know if I can swing the $5,500 for the EFI, fuel pump or pump/tank combo, fuel lines, controller, on top of the cost of the build. I may have to start with the Promax modded Holley carbs, but it would be ideal if I had the EFI for the builder to dyno my engine with!

 

[biomedtechguy]

One of the BEST reasons for going to the F&B direct port injection 3x2 EFI system, other than EXTREME "bonus coolness points" is that the "problems" inherent in the Weiand 6bbl intake are all ELIMINATED by making it a "dry manifold". I have the ONE edition of the Chrysler Performance manual that has ALL the race teams published modifications for ALL of the aftermarket intake manifolds available at that time, including the Weiand 6bbl. I'm actually more inclined to follow the advice of the guy who has the pictures of his mods to the intake featured in the Victory Library article on the Weiand. Several reasons, but mainly because he got better results than the Chrysler Performance bulletin mods, and they are more easily reversed, for the day I convert to EFI.
I have been told by a few guys who have run and are still running (10+years) the Weiand intake to try it as is and go from there. The only mod that has been done is the sharp 90° angles from the plenum floor into the runners have all been nicely radiused, as per the Chrysler Performance bulletin, and THAT doesn't hurt ANY application.
Look at those pretty radiused intake runner ports...

I intend on having the runners further cleaned up, since they have to be brought out to Max Wedge size for the TF 270s, and I'm told to check for runner to head port alignment (I'm going to use a scope camera). So the imperfections that are visible will be taken care of in the future.

 

[QuickBpBp]

I just asked another forum friend about that, supposing that such a device existed. Throttle actuated microswitch closes, timing retards, outboard carburetor lean spike passes, nitrous and extra fuel enter...all within about 1.1 seconds...
OR when you say "nitrous was powered" do you mean arming the system (powering it on)?

Yes...