Thoughts on Nitrous?

"BJohnson11" (brettjohnson01) 12/31/2013 at 00:31 • Filed to: truck project

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So ScarJo has been running good, and I've gotten a lot of the electrical issues worked out over the past couple days. Still am tracking down the battery drain, but now I at least have working taillights, turn signals, and headlights. I've also kinda ran out of performance mods to do. Trans could use a shift kit, I definitely want to throw in an Eaton LSD and higher gearing, but for now, I'm thinking about what the next engine upgrade could be. My big block motor has low compression heads, and throwing new heads on is kind of out of the question. The goal is to keep the truck running while doing any sort of project, and a full motor build is too much for that idea. Plus, my budget is fairly slim.

So after all that rambling, I'm thinking nitrous. Sure, a blower would be awesome, but a nice Weiand blower is like 3 grand. A nitrous kit could only be a few hundred bucks, and with about a 100 shot of nitrous, I could safely bump power. Thoughts?

IDROVEAPICKUPTRUCK > BJohnson11 12/31/2013 at 00:33

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What is the goal of the project? Drag strip or just general hoonage? If drag strip then sure why not, if this is just for general hoonage I'd skip it and save the money for the next thing that breaks.

BJohnson11 > IDROVEAPICKUPTRUCK 12/31/2013 at 00:36

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A little bit of both. The goal of the truck is to have a fun, fast, truck that gives me something to work on, but I also am planning on dragging it. Nothing too serious, but I want to be able to take it to the strip and have fun. Yea, thinking it over, nitrous seems excessive, but I mean, I can't help it....More horsepower = more fun.

E30Joe drives a Subaru > BJohnson11 12/31/2013 at 00:37

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Give a man nitrous and he goes fast for a day, give a man a blower and he goes fast for a lifetime.

GhostZ > BJohnson11 12/31/2013 at 00:39

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You didn't even consider a turbo? You could slap together a turbo kit with about the same HP gain as nitrous, except it wouldn't cost refilling and without destroying the engine, for only a few hundred bucks more probably.

To be honest, modern supercharger kits/blowers are way overpriced for their performance gains, and they really hurt the drivability compared to a turbo.

JGrabowMSt > E30Joe drives a Subaru 12/31/2013 at 00:39

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Remember kids, bottles are for babies.

GhostZ > BJohnson11 12/31/2013 at 00:42

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How much HP are you getting now? What parts have you put on it already? On a mostly stock Big Block, a good solid lifter cam, intake, and heads will net you more gain than a blower out of the box.

BJohnson11 > GhostZ 12/31/2013 at 00:47

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I'd guess around 350 hp and 450 lb ft of torque. It's got stock internals with an intake and carb. Cam is next on deck, but the problem with a cam swap is it leads to new Springs and lifters which leads me to might as well swap heads while I'm at it. Which gets expensive.

BJohnson11 > GhostZ 12/31/2013 at 00:48

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I could, but turbos on carb engines don't result in the most tunable engine out there. I guess I hadn't given it much thought though. I shall look into it.

GhostZ > BJohnson11 12/31/2013 at 01:13

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(to repsond to both of your posts)

Turbos on carb engines work the same way a blower does, it's called a 'blow through' setup. They're not common but they've certainly been done. Alternatively, EFI kits are dirt cheap too. If you bite the bullet and get a high-spec EFI kit with ITBs, you'll probably have the best power gain without sacrificing reliability. Getting that motor to breathe and flow properly and at higher RPMs is paramount to making decent power, since they were sort of restricted from the factory. It has displacement and strength, it just needs to be untapped.

These guys here: http://www.superchevy.com/technical/engi… (which I'm sure you have seen if you've googled big block build ideas) got their peak power up to 5500+ RPM by bumping the peak torque that high. The result was 565HP. Only THEN was NOS really a benefit, after the rest of the engine was opened up.

So here's what I propose:

1. Decent EFI system (pay for it by selling your carb and intake when you swap it, someone out there will buy it) plus an intake for it (ITBs if you're crazy, plenum if you're sane) this might get you a tiny power bump, but really its all about being able to flow the right amount of fuel and air. It won't increase power now, but after heads and cam, it will. The whole goal of this is to improve volumetric efficiency and intake velocity, both of which (unlike a turbo, Nos, compression, etc.) will amplify the gains you get from any other mod after this point.

2. Moderate duration Solid lifter cam, so you feel safe revving to 6000, with appropriate heads, springs, and pushrods. This is where that intake will really shine, because a single 4 barrel carb won't do if you're trying to rev the motor out higher and get more power. An EFI system can be mapped so you can get double-digit fuel economy without choking off your fuel supply at higher RPMs. If this doesn't put you over 450 HP easily, then you've got a huge problem.

3. Blow-through turbo with strong pistons and con-rods, and intercooler, and possibly methanol injection. Maybe get some shorter compression height pistons and longer connecting rods, that will reduce mean piston speed at peak RPM, keeping the G forces on the piston down, so you don't risk throwing a rod as much. At this point, if the power doesn't blow your transmission or diff, then you're doing something wrong.

To just give you an idea, if you get spinning to 5500 rpm (this puts mean piston speed at about 3666 ft/m, which is a safe value, over 4000 needs modern parts, Nascar/F1 runs 6000) and bring your VE up to about 95% (which is actually quite bad) you get 460 reliable HP. 6 PSI of boost through that, which isn't difficult to achieve either, is about 700HP.

GhostZ > BJohnson11 12/31/2013 at 01:15

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Correction to my last post, EFI kits for big blocks are more expensive than I thought (I was going of of SBF EFI kids, which I know) but still worth it if you plan to modify on top of it.

BJohnson11 > GhostZ 12/31/2013 at 02:45

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Yea I wanted to do EFI, but I didn't want to drop 2-3 grand into the motor. Solid lifter cam is on deck, but the other thing with my motor, is because of the heads it ha (peanut port heads, look them up if unfamiliar) make all their power down low, and wont flow much past around 5500 rpm. So the motor is a torque monster, but won't reach high hp numbers with the heads it has. So while new heads would be nice, I dont want to/have enough money to dump into this motor and project to get it there. I was kinda just looking for a quick and dirty way to get more power.

If it was a full blown, bigger budget build, sure, I'd go EFI, look at forced induction, and build the whole motor. But that is unfortunately not what this build is.

CammedCTSV > BJohnson11 12/31/2013 at 16:56

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Dont swap heads, but new ROLLER cam, springs, locks & valve seals. You will be happy!

CammedCTSV > CammedCTSV 12/31/2013 at 16:56

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Ooops, I meant this in reply to the OP