PDA

View Full Version : Nitrous



JimCT
03-13-2007, 05:37 PM
It seems like everyone has tried just about everything here. Has anyone done a mild nitrous system? Just enough to get you over that big ledge?

jp-
03-13-2007, 06:12 PM
Yes, Nitrous comes in handy when you need that extra boost to get you up and over when rock crawling. As a matter of fact, I find that when in low range and using nitrous, my 40:1 ratio actually allows me to go 45mph! The engine does seem to get a little hot though, while continuously running above 6500rpm; but this is no serious problem as my 2.25 has been balanced and blueprinted.

CliftonRover
03-16-2007, 01:54 AM
Could nitrus be a solution for those long vermont hills? Or is it for no more than 10 second bursts. I've seen setups where the nitrus is triggered only when floored, this might not be a good idea as I consistantly floor my 88". The engine is in good shape, i just drive fast.

leafsprung
03-16-2007, 02:00 AM
If you need more gusto, consider a motor swap.

yorker
03-16-2007, 07:39 AM
It might be better to think about your 2.25l as a nice tractor engine and your LR when so equipped as a REALLLY FAST 8n tractor. :D

They weren't geared or engineered with the thought of going very fast or traveling the US interstates. To do so you need to re-engineer a lot, a shot of nitrous isn't really going to accomplish that for you. Get a NP435 and 302 and a Sals rear axle if you want more power.

Mike Koch
03-16-2007, 08:29 AM
Before altering your Series to boogie any faster than Solihull had in mind, please consider the condition of your brakes.:nono:

Mike Koch

jp-
03-16-2007, 11:40 AM
Before altering your Series to boogie any faster than Solihull had in mind, please consider the condition of your brakes.:nono:

Mike Koch

That's what the car in front of you is there for, of course it is considerate to honk first...

JimCT
03-16-2007, 04:30 PM
This has nothing to do with speed. It has to do with momentary HP. Our fully loaded ambulance/camper is fine on teh road, we just take our time, and fine 99% of the time off-road, but every so often there is a situation off-road that coudl use a bit more guts. Seems a tiny shot of nitrous might be easier than lower gears, bigger engines...and all that. I really am talking about probably a second or two of boost.

I Leak Oil
03-16-2007, 04:57 PM
I've tried nitrous....once....
Jason T.

yorker
03-17-2007, 07:21 AM
Jim,

What other mods have you done to your engine so far? Nitrous would be the last thing I'd try, I think I'd even consider a turbo before Nitrous.

JimCT
03-17-2007, 07:41 AM
Took off the military fan, use an electric fan most of the time, electronic ignition, Weber non-progressive 38/38 carb with K&N air filter, pierce manifold, less restrictive exhaust, Mobil ! in the engine and Red Line in the rest. 255/85-16 Truxus tires.

TeriAnn
03-17-2007, 10:41 AM
Jim,
What other mods have you done to your engine so far? Nitrous would be the last thing I'd try, I think I'd even consider a turbo before Nitrous.
When Land Rover tried a turbo, they quickly realized that it would beat a 3 main engine to death. Hence the introduction of the 5 main 2.25L engine to support a turbo diesel.

The goal should be enough reliable power to allow you to drive where you wish without over stressing the engine.

Personally I thought it was exciting when the engine ran out of power and ground to a stop when doing a steep technical climb in low range first. Especially when I could not see much of the trail behind me because of the high window placement of a lift gate. I got to rely upon the legendary effectiveness of 109 brakes in a steep uphill location. Ah, the adrenalin rush.

I don't get that adrenalin rush so much anymore with front disc brakes and a nice http://www.tjwakeman.net/v8s.gif

yorker
03-17-2007, 12:42 PM
less restrictive exhaust

how so? what diameter?

I think you've maxed out the real potential, a cam and some head work might be beneficial but $ for $ to get any extreme improvement you are going to be headed towards a different engine.

Disc brakes are great unless you happen to stall and lose vacuum. That is the only situation I've ever been in where I had an issue with them. 109 drums wouldn't have been much better in that situation I expect...
With discs I think a vacuum reservoir is a really good idea.

Bostonian1976
03-17-2007, 01:53 PM
my 2.25 has no problem whatsoever with the long VT hills. Is that unusual?

yorker
03-17-2007, 09:02 PM
No, you drive an 88, I'd guess you are probably 600-1000lbs lighter than a well loaded ambulance. At least if you consider Jared Ivy's(kingslug) ambulance's weight.
A good 2.25 should do OK in an 88.

JimCT
03-18-2007, 07:34 AM
6200 lbs loaded for a month of camping with the two of us and our 115lb dog.

yorker
03-18-2007, 08:21 AM
You are a prime candidate for a repower since that really is a ridiculously low power to weight ratio.

Generally speaking the torque-to-weight ratio is what really counts. In today's usage ≥ 20:1 is considered inadequate and < 10:1 is overkill.
Yours is around 52:1... using the 2.25's figures from TAW's page:
http://www.expeditionlandrover.info/enginePwrSpecs.htm

Neither a Turbo nor nitrous is going to make much of a difference for you.


Ask TAW- I think that summer trip she took to go to the ANARC Ralley @ Greek Peak in '98 was the nail in her 2.25's coffin.


A Ford 302 EFI like what she has now can vary widely in torque but figures of 300lb ft aren't uncommon IIRC (stock figures for the 5.0l were
150 hp (112 kW)270 lb.-ft. at 2,000rpm.

That renders a 20:1 ratio with your weight. Better than an unladen 88 with the 2.25 so that isn't bad by our somewhat eccentric standards. ;)

TAW-have you dynoed your engine with the EFI? What are the engine's build specs now that you have swapped?

TeriAnn
03-18-2007, 05:28 PM
[quote=yorker]how so? what diameter?

One diameter up from stock exhaust tubing plus a free flow muffler is your best bet. Your local muffler shop can bend you up a set. It will help over stock but considering how much an ambulance weighs you may not notice a difference. :(

TeriAnn
03-18-2007, 06:16 PM
Ask TAW- I think that summer trip she took to go to the ANARC Ralley @ Greek Peak in '98 was the nail in her 2.25's coffin.
It performed just fine for that trip. Though I did have the engine floored for a lot of the trip. I had already made the decision to repower my Land Rover before that trip. I was exploring engine and gearbox possibilities.

The final nail was when I was driving South from Canada in Eastern Montana a few months earlier. It was a 2 lane highway with a long bend around a low bluff. I was floored at about 55. There was an oncoming 18 wheeler plus a 18 wheeler coming up behind me about 25 MPH faster than I was going. It had the space and passed me before the oncoming 18 wheeler got too close. It turned out that there was a second 18 wheeler behind the first also trying to pass me. There wasn't time for the second 18 wheeler. The driver thought better me than him and pulled into my lane alongside me to avoid a head on with the oncoming 18 wheeler. Rather than get run over I took this as an oppertunity to so some off roading at speed. I was able to safely get the Green Rover stoped out on the field. My poor dog was pelted by the few things not secured in the back (I had a net between the front & back) and I thought I was going to put my head through the roof on some of those initial bumps. But no damge was done except to my sense of safety. If there had been a drainage ditch along side the road the Dormobile would probably have tumbled head over tail a few times. When I stopped shaking I decided it was time to either sell my Land Rover or switch engines.

That was just the last of many close calls I've had by stupid impatient drivers just because I could not keep up with traffic. There are some highways in Utah where I could not even go the posted minimum speed limit on grades.



A Ford 302 EFI like what she has now can vary widely in torque but figures of 300lb ft aren't uncommon IIRC (stock figures for the 5.0l were
150 hp (112 kW)270 lb.-ft. at 2,000rpm.
The stock HP varied all over the place depending upon year and how it was built. 1970's 302s were pretty gutless, as were most truck versions & non-sporty passenger cars.

My base engine is from a 1970 Mustang. The EFI is stock 1991 Mustang 5.0 Mustang 302/5.0 (except the Mustang II years) typically were factory rated between about 205 HP and 240 HP with the limited edition sport version higher. I'd guess my engine is somewhere in that range. I know it will out climb a 4.6 P38 Rangie climbing the mountains going East to Reno :D

150 HP @ 2000 RPM sounds about right though.



TAW-have you dynoed your engine with the EFI? What are the engine's build specs now that you have swapped?
I never felt a need to pay someone o find out the actual HP. The engine does what I want it to do on regular petrol. I figure that's what really matters.

1970 Mustang motor, 1991 Mustang EFI, afer market 65mm throttle body (stock is 60 mm, the after market was cheaper than a new stock one). hooker headers, no mechanical fan (I have an electric fan off a Mercedes V8). When it comes time for a valve job, I will consider aluminum heads (makes the engine lighter than a stock 2.25L petrol) The heads I have in mind provide better power at the low end than stock. I'm also thinking about a special truck cam optimized for low RPM torque. But all that can wait until I have to pull the heads. It meets my needs right now.

JimCT
03-19-2007, 11:04 AM
Just for interest we have done over 35,000 miles in the ambulance as it is, so I would not consider it unuseable. That had included trips to cape Breton, PEI, NB....and lots of off-roading, it has been on it' sside once.

yorker
03-19-2007, 11:24 AM
Well if you want to try nitrous- go for it. Let us all know how it goes.:thumb-up:

TeriAnn
03-19-2007, 12:36 PM
Just for interest we have done over 35,000 miles in the ambulance as it is, so I would not consider it unuseable. That had included trips to cape Breton, PEI, NB....and lots of off-roading, it has been on it' sside once.

I think you have hit on the single most important thing. Best to stay with what works and you are satisfied with.

I've seen too many people buy a series rig and trick it out without first learning where the vehicle handling boundries are. Sometimes the trick stuff can make the handling worse or the vehicle less reliable. A lot of times it becomes a crutch for not knowing how to drive a Series rig. I think Jim is taking the right approach. Buy a series rig and drive it. Learn where the vehicle handling boundries are, live with the ones do not feel a need to exceed, then selectivly make modifications to specific parts that will affect the boundries you wish to increase. It is usualy best to be conservitive with the modifications as long as the end results meets your needs.

If he can meet his needs by picking up 5 or 10 HP or straping JATO units to the roof of his ambulance ... Opps thats a nitro, er nitrous system isn't it, then that's the way to go.

Give you ideas a try & see if they met your needs.:thumb-up:

KingSlug
03-19-2007, 11:31 PM
I was pretty much satisfied with the power from my amby, but I found that it just wasnt driveable with modern cars. People would squeeze me out in passing lanes, cars were constantly causing me jumping in front of me as I was building speed causing me to slow. If I can get to 55mph I do fine. On hills I pull to the side and plug away at 15-20mph, from start on a hill its slooooow. I have decided to go with a 4BT Cummins, it just makes sense with the weight I am pulling. The problem with getting up hills is that your amby is giving all it gots to stay going forward, without a bigger engine you just have to enjoy the slow lane. Nitrous destroys engines, even in small amounts. The mods I currently have 8:1 head, Rochester, larger exhaust and I try to strip out extra gear when I am not going camping (I even rely on only one front fuel tank, instead of filling up all 3).