Performance tuning the Stag engine

[flying farmer]

Assuming you have the timing correct it is probably just not getting enough fuel.

On the start/idle settings check the warm up enrichment is approx. 150% on the first step above zero degrees.

If that is about right the simplest thing is to simply scale up the whole fuel table. Highlight the whole table then click on the little star icon at the top. It will open up a tab telling you to scale the table, I would add about 10% then try again. If it is a bit better try another 10% until you can get it running. If it is worse try scaling the table down instead.

Neil

[Stagdad]

Steve

sounding good,is there a lot of messing around with the software/setting up

dave

Dave, I've had a lot of crap laptop issues and ive also think I've got a few Ms software issues but it's hard to tell because I have no experience of it to call upon although lots of help on forums and Facebook . I'm slowly getting my head around it and understanding more. One simple setting can throw you off the sent and go looking for things to solve a problem that isn't there. Still it's a hobby so it doesn't matter. I now have it firing up smooth but unable to keep going. http://youtu.be/4Nou-aOS3WI.

[new to this]

Some great work there Neil, must take you ages as well as cooking the brain somewhat.
http://youtu.be/7v3sHnDiKeA. I'm getting there but a lot of software hiccups at the moment. As soon as I can get it to run properly I will tune it to a smooth idle then drop it in the car and get Shaun at MStune to sit in and get it somewhere close then on to the rolling road.

Steve

sounding good,is there a lot of messing around with the software/setting up

dave

[Stagdad]

Mickey is spot on with this comment, but then his forum name rather gives a clue that he might have some experience in this area!

To answer Ians comment however, looking at the torque and power graphs first move would be a set of tubular manifolds.

When I get to the end of this thread I shall try and add a few informed comments to help anyone who wants to tweak their Stag engine.

This might take a while yet as what I am really going to need is some rolling road results from the other guys building efi systems who are using the normal tubular manifolds and standard cams.
I don't have any engines built to this specification, my Stag with standard cams has a home made exhaust manifolds, and the Estate has Pheonix manifolds but no injection.

Neil

Some great work there Neil, must take you ages as well as cooking the brain somewhat.
http://youtu.be/7v3sHnDiKeA. I'm getting there but a lot of software hiccups at the moment. As soon as I can get it to run properly I will tune it to a smooth idle then drop it in the car and get Shaun at MStune to sit in and get it somewhere close then on to the rolling road.

[flying farmer]

All of them, performance increases of any note mostly come as a win,win,win package where the incremental increases are picked up and magnified by the next performance part.
Beware of the fit this gives you 8hp, fit that gives you 4 hp etc school of tuning, mostly leads to disappointment especially what you really do want for a road going car is good "ol" torque instead.

Micky

Mickey is spot on with this comment, but then his forum name rather gives a clue that he might have some experience in this area!

To answer Ians comment however, looking at the torque and power graphs first move would be a set of tubular manifolds.

When I get to the end of this thread I shall try and add a few informed comments to help anyone who wants to tweak their Stag engine.

This might take a while yet as what I am really going to need is some rolling road results from the other guys building efi systems who are using the normal tubular manifolds and standard cams.
I don't have any engines built to this specification, my Stag with standard cams has a home made exhaust manifolds, and the Estate has Pheonix manifolds but no injection.

Neil

[mike@thenook]

When I had my Holley fitted I changed the primary 51's for 48's on the advice of Ian at Monarch but never changed the secondaries-it did run very well with the 48's but there just wasn't the low end torque that's available with the stroms particularly as I now have the updated HRS needles and springs.

[mjheathcote]

They come fitted with 51s as standard IIRC, I swapped mine out for 49s on someone's advice but I can't remember who that was. It might have been TH.

Might have been me possibly.
I swopped from 51's down to 49 on the primary, then fitted the removed 51's to the secondary...replacing the jet plate for one that takes screw in jets.
It was far too rich running on the 51's.

[Motorsport Micky]

All of them, performance increases of any note mostly come as a win,win,win package where the incremental increases are picked up and magnified by the next performance part.
Beware of the fit this gives you 8hp, fit that gives you 4 hp etc school of tuning, mostly leads to disappointment especially what you really do want for a road going car is good "ol" torque instead.

Micky

[Ian F]

Neil

I only have one thing to add:

If you need a bog standard Stag engine ripe for improvement - to test anything else, then can I volunteer my car. No charge as long as I can keep the bits of course!

I would never have the skill or patience to try any of this, but I suppose that's how these tuners and aftermarket tuning parts makers make their money. Great thread - keep it going.

However if I was to fit 1 single item to improve performance/power/torque - what would you think best? Carb/Headers/Exhaust??

Ian

[Goldstar]

Do you know what jets you have fitted Nambo?
sounds as though you may have it jetted for a Rover 3500 engine as mine was originally

They come fitted with 51s as standard IIRC, I swapped mine out for 49s on someone's advice but I can't remember who that was. It might have been TH.

[Kevin Garrod]

I have a Holley on my Stag, I also fitted a lamba and fuel ratio gauge which tells me it runs much too rich when I give it some welly.
Trouble is, it is infrequent to find a stretch of road long enough to really know whats going on and I also wish to keep my licence so, is there such a thing as a fella with a rolling road and the parts/knowledge to set up my Holley within traveling distance of South London?

Try Fast Parts, Tait Road, East Croydon.

[mike@thenook]

Do you know what jets you have fitted Nambo?
sounds as though you may have it jetted for a Rover 3500 engine as mine was originally

[Nambo]

I have a Holley on my Stag, I also fitted a lamba and fuel ratio gauge which tells me it runs much too rich when I give it some welly.
Trouble is, it is infrequent to find a stretch of road long enough to really know whats going on and I also wish to keep my licence so, is there such a thing as a fella with a rolling road and the parts/knowledge to set up my Holley within traveling distance of South London?

[flying farmer]

I was rather surprised at the lack of top end power with my new manifold, so I started doing a bit of internet research on modified Rover V8 inlet trumpets.

There are a huge variety of options available for the Rover engine, one being a set of flared carbon fibre trumpets that would fit in the original trumpet base that promised all sorts of wonders.

Fortunately these expensive trumpets wouldn't fit, but the general consensus was that to get a Rover V8 to rev it needed shorter trumpets.

Since the TV8 is a more revvy motor than the Rover this seemed like the best option. I quite liked the flared carbon trumpets, so decided to combine a bit of shortening and flaring at the same time.

One of the first rules of engine tuning is never to change two things at once as you will never know what has given the benefits. I had already broken this rule when I changed both the cam and the inlet manifold, and I thought that the changes to the trumpets really only counted as one thing. I was to find out later that shortening and flaring definitely count as two different things.
This was to come back and bite me firmly on the arse several times over the next few years, but the first time I got lucky.

Below are consecutive rolling road results with the only change being the modified trumpets.
TR power runs 2009 and 2010.jpg

As you can see an extra 44bhp and huge gains in torque right through the rev range, but particularly at higher revs. This, as I was to find over the next few years, was beginners luck!
Neil

[flying farmer]

Having decided I needed a better injection manifold, I looked at a variety of options including 4 pairs of PI saloon manifolds as the port spacing is very similar, but the distributor was in the way and I felt it was a step too far to go to a distributorless ignition system at that time.

The simplest solution was to use a Rover plenum top, and I realised I could modify the plenum base to suit the different port spacing of the Stag engine.

I got good results with the engine in the TR, so when the engine on my first Stag decided to commit suicide, I rebuilt it with injection and copied the TRs manifold with a few modifications. This time I took photos as I did it and put the picture on photobucket with an explanation of what I was doing.

Can't believe its already 5 years ago!

http://s740.photobucket.com/albums/xx44/stagpowered/Building%20a%20Stag%20EFI%20inlet%20manifold/

Lots of things had changed by the time I built the inlet manifold for the project Stag, flow bench testing had shown the best angle of the port entering the head was slightly downhill, not uphill as in the photobucket pictures. Also the fuel rails I had used on the previous two manifolds were no longer easily available, and the different angle of the inlet runners made the fitting and retaining of the injectors a different proposition altogether.

The steeper angle of the inlet runners meant keeping the Rover plenum base was also no longer an option. This did not bother me as previous experience had shown the construction was difficult and time consuming and it was easier to make a complete new plenum base.

The relevant area of inlet manifold construction starts on page 33 of the Flying farmers new project thread, and the differences between the photobucket example and the latest design can be seen.
My first attempt at inlet manifold construction used a completely unaltered rover plenum and trumpet set. Since I had no idea whether the inlet trumpet set up would be suitable for the Stag, there was no point in trying to modify it.
First set of rolling road results surprised me as the car felt much quicker, so the fact I had lost a couple of horsepower came as quite a shock!

Big increases in torque both at the bottom end of the rev range, and in the mid range were the reason it was quicker, though it did lose out slightly at high revs compared to the modified Stag manifold.
stag vs fabricated manifold.jpg

Standard Stag engine torque curve is in red again.