NITROUS OXIDE ( nos / n2o ) advice forum

Damn! We just scrapped my sons Escort!! It had a 4.6 rover with WoN fitted. It was a Mk6 Escort with RWD conversion but it was suffering from too much rust so we sold all the runnig gear and dumped the shell in my mates yard for scrapping 2 weeks ago.

Sorry Trev!

My new engine build spec has now hit "mission creep" as they can do ??

Despite all the money I have put into my 50 year old SBC 350 block I'm not happy with it. So I have just ordered a new Dart SHP block for the new project. I have already sold the old block to add funds to the new build. The old block was tired and already bored +60 which isnt what i want for a drag rwce engine.

The new Dart block can be bored out to +165thou and still give me bore walls 1/4" thick? So this lump can be taken to 430ci with no problems?

Perry

Bugger that would have been ideal and I've no doubt, that the new owner could have replaced the rusty parts, with G/F parts and it would have obviously been lighter as a consequence.

Please keep your eyes and ears open for ANYTHING that might be suitable please, as there's no immediate rush.

Sounds like you're getting super serious about this plan Perry!!!!!!

I am Trevor.... I have decided to limit this first new build with the new block to a 383ci config aka 6.3 litres in the MGB. I think that a rock solid 383 engine build with this block along with forged crank, rods and custom pistons with my Brodix DS225 heads and all the other parts I have collected over the last 18 months for the new build are going to come together to give me an engine that will run low 9's and high 8's while not being stressesd in any way

I have spent many years with rpm limited Rover V8 engines, which have done me proud to be honest. But for this build I want a big cc high rpm engine. The rovers used to max out at 5300 across the line. The new SBC build will be capable of 7500rpm?

But my main concern is where the new engine makes peak torque eh ?

Back in the day I was going on about how i was going to modifiy my RV8 engine and make it quick. I have done that now and I was happy with mid 9's on track. I rebult my old engine and its now sold. The new SBC engine will be ready for final assembly in 8 weeks.....Then I need to make it fit my engine bay and hook up the tranny. Then i need to wire in all of the new electrics, MSD Digital 7 etc and fit wheelie bars. I was hoping to have the car ready to roll in July this year. But I have to be real and say that I think I will be doing shakedowns by late September be ready for the 2017 season??

This means that the MGB will have been off track for over 2 years. But when it comes back it will run in the 8's and piss a lot of folk off at the Mopars

You should have spoken to me about your Rover engine spec, as I had mine rev to 8,000 + but now that I know better, I'd actually build an engine for lower rpm for the following reasons;

1) RPM is the engine killer
2) Nitrous is more effective at low RPM
3) Torque is more important than power

I've had other customers start off with a low rpm motor who then reworked it for high rpm, who then switched back to the low rpm spec as it produced better results.

Torque is more important than Horse power for Drag racing..... ???

Trev!
I have been having this argument with several folk in recent weeks. This debate got started over a newbie post on a car forum. The post was basically "what is the best RPM to shift gear at for max power and performance"

There were many folk who said that the guy should get his car in a dyno and log peak hp as thats where he should be shifting gears... I had a right royal battle about this until I ended the converstaion with

"Listen up... I drag race my car. Thats a standing start to a finish line a 1/4 mile away. If I run my engine to peak hp RPM and then shift it will run XX seconds on the 1/4 mile. BUT if I run my engine to peak torque RPM or just over that my RPM drop in the gearshift takes me just below my peak torque RPM so I can get another push in the back from the next gear. That takes nearly 2 seconds off my ET on the strip"

The conversation pretty much ended with "Hey, this guy with the MGB has been there and got the Tee Shirt. So his track testing has answered the question I think" ?

LOL

Hp is the byproduct of torque and rpm. Shifting just below the peak torque is what will give you the best acceleration. The hp is only the overall work an engine performs.

Two engines can have the same peak power yet the one that has a broader torque will win the race.

You're pretty much correct Perry but there's a little bit more to it than that;

1) If you plot a graph of torque it's the AREA UNDER THE CURVE that equates to 'work done' (acceleration)
2) To achieve optimum acceleration you want to keep the engine working over the range of RPM that gives you the maximum area
3) If torque rises slowly to a peak at say 3,500 rpm but then VERY slowly drops off for 3,000 rpm, it should be better to shift later than peak torque.
4) If torque rises quickly and stays relatively high before reaching peak torque at say 3,500 rpm but then VERY quickly drops off for 3,000 rpm, it should be better to shift at about peak torque.
5) In its simplest terms you want to use the range of rpm that represents the highest AVERAGE torque figure.

I hear you Trev

Mission Creep sets in Deeper now

As I've decided to put the roll out back to July 2017 I'm saving for more stuff. Next item to be added to the shopping list is a belt driven vacuum pump system.
The list is growing again for sure.

I'm not sure if I mentioned this before! But I'm considering investing in having the engine tuned on an engine dyno before it goes into the MGB.
I will have to trial fit the new engine so I can work out where the new engine mounts need to be on the chassis but then it can come out and be finished ready to fire up. I am making enquiries now about how much it would cost to be bedded in and then tuned on a dyno. I guess as its got a mechanical roller cam there wont be much required to bed the cam in like I used to do with my old hydraulic cams? But the rings will need settling in, and doing this under some load would be best I think.

I have no doubt that I could build the engine and guess at a reasonable tune on the twin carbs but that will mean lots of test passes on track and then looking at data logs to make minor adjustments and then queue up to run again etc etc.. This could take several weeks of track testing at RWYB events where I may get 2-4 runs in a day eh? And that before I even think about turning the gas on to test all over again. So I'm thinking 4-5 days at the track for tuning runs off gas will cost me around £400 ish when I could be working overtime on those weekend days and earning around £800 ish? I think that makes it a no brainer to be honest?

The block is now part built and despite the Dart specs saying that the block will clear a 383 stroker kit (as it has been cast with cut out where required) I've used bigger con rods with an ARP upgrade kit so I need to take around 2-3mm out of the block here and there to prevent the con rods fouling. So far it looks like the low base circle cam will clear the crank and rods

While all this is going on over the next 10 months or so I need to do a lot of other work on the car and make my mind up about how I am going to build the new nitrous system? I dont intend to ditch FRED as he's been good for me so far. I'm thinking that I will stick with crossfire plates as I like them. Direct port would be good as my inlet manifold has lots of room to fit nozzles but I dont want that much plumbing on the engine. I do however want the nitrous system to be able to deliver around 500hp if I should want to, so I may invest in new pulsoids. One pair for each carb rated at 250hp. I'm sue the plans will change as the rest of this year moves on. But at least I have a basic plan in place

If the Crossfires are 2 per side on opposing sides in the correct orientation, they would be better than a DP system anyway.

That was my thought Trev !!

One crossfire facing down into each of the 8 runners side mounted on the plates. This would give good atomisation for all 8 runners while still seeing a little free space in the primary chambers just under each carb for the fuel mix that doesnt go directly down each runner to be shared across all 4 runners under each carb if that makes sense ?

The MGB's new Dart SBC engine is now almost ready ???

It looks cool but there are still lots of small things to do to make it ready for the engine dyno in November.

Carbs need a complete overhaul. Carb linkage / Scoop linkage needs setting up properly. Starter motor needs fitting and setting up, MSD trigger wheel needs a spacer made so I can bolt the engine cradle under the pickup bracket, I still need a dipstick + modify the Brodix exhaust flanges to suit the head ports + thermostat housing and stat required + I need to make a set lof lifting brackets for the engine.

I havent even thought much about the final plan / layout for the Nitrous system yet?

I will ideally use 2 nitrous plates with four x 250hp pulsoids so i can tune with up to a 500 shot when the time comes. For the time being I need to decide whether I'm going to tune with pump gas or race fuel when it eventually hits the engine dyno?

I'm hoping it will hit the 600hp I want on pump gas on the engine dyno before Xmas?

I'm sure if you put you're mind to it, Perry, you'll accomplish your goals by Xmas.

Your build is looking quite nice!

Ha Ha!!
Mission creep has set in yet again
Engine dyno day has now been pushed back by 3 months as I intend to fit a pair of new matched race carbs that will be made to order. The old Holley 600 double pumpers are way old and oversized for what I want on this engine. I still want the look of the holley carb style but I need carbs with modified boosters that will still atommise my fuel correctly at 40% less air velocity in the venturi's. I need to ensure that when the car hits the strip for its test runs the fuel delivery will be spot on so i can max out the (no nitrous) performance. If this goes according to plan the MGB will still pull 9 seconds with no gas

Then the Won parts will be dug out of the box for the end of 2017 so i can build a new system

Perry

WoN parts in still in a box? Blasphemy!

Sounds good, Perry!

I love seeing the updates and plans for your car Perry Takes my mind off of the constant rain and fact that I can't get out there and do anything with either of mine Looking forward to more pics.

Update still in progress

Perry,

Yours is probably the build I've read the most on the forum (closely followed by scaldedcat) - glad to see it is still underway! Serious upgrades -- Best of luck this year!

i have always followed Perry's adventures ... Brett was another member, but two years ago trev was asking where has he gone,so hope hes still out there..

It's unfortunate that we don't hear from Brett or other former 'regulars' anymore.