Discussion
On a 500 and at max revs like 7000 there might be a benefit but as it’s limited to 6200 I’d say any gain would be marginal if anything noticeable.
What length are the trumpets on a 500.
I asked one of the most informed guru about lots of these mods once and this one I was told a waste of time. Shorten your trumpets a little would achieve the same effect in air space.
If you are thinking of trying one of these firstly place something the same size on top of your plenum and make sure you can close the bonnet.
The likelihood is you will have only a few mm spare so do check.
When I mentioned the benefit of the extra air space at high revs he asked me how often are you likely to be driving at or near the limiter and for how long. It’s not long enough for it to be starving of air. In summery unnecessary and many people using standard plenum are still pushing well past 325 bhp.
If it feels good do it but when valves open overlap and close they suck air in and gases are forced back up through the trumpets in quick succession, raising the plenum height increases the length of those shock waves hitting the top of the plenum and slowing them down. There’s a lot to induction tuning. Others may have a different view but I’d not bother with it personally.
A better investment would be ACT induction kit and new air filter imho.
What length are the trumpets on a 500.
I asked one of the most informed guru about lots of these mods once and this one I was told a waste of time. Shorten your trumpets a little would achieve the same effect in air space.
If you are thinking of trying one of these firstly place something the same size on top of your plenum and make sure you can close the bonnet.
The likelihood is you will have only a few mm spare so do check.
When I mentioned the benefit of the extra air space at high revs he asked me how often are you likely to be driving at or near the limiter and for how long. It’s not long enough for it to be starving of air. In summery unnecessary and many people using standard plenum are still pushing well past 325 bhp.
If it feels good do it but when valves open overlap and close they suck air in and gases are forced back up through the trumpets in quick succession, raising the plenum height increases the length of those shock waves hitting the top of the plenum and slowing them down. There’s a lot to induction tuning. Others may have a different view but I’d not bother with it personally.
A better investment would be ACT induction kit and new air filter imho.
Classic Chim said:
A better investment would be ACT induction kit and new air filter imho.
The ACT carbon trumpets on the standard plenum is a good upgrade compared to the scaffholding tubes the factory used:OEM Hotwire plenum trumpets from landrover and as fitted to many tvrs (top), OEM TVR 500 scaffold pipes (middle) and ACT Carbons:
The 500 trumpet base features enlarged trumpets (45mm iirc) - most other tvr's used largely bone stock 3.9 landrover stuff. Even the 500 had bone stock 3.9 injectors running 100% duty cycle and a bit lean for comfort.
Photos from my Rover V8 inlet manifold archive.
eliot said:
The ACT carbon trumpets on the standard plenum is a good upgrade compared to the scaffholding tubes the factory used:
OEM Hotwire plenum trumpets from landrover and as fitted to many tvrs (top), OEM TVR 500 scaffold pipes (middle) and ACT Carbons:
The 500 trumpet base features enlarged trumpets (45mm iirc) - most other tvr's used largely bone stock 3.9 landrover stuff. Even the 500 had bone stock 3.9 injectors running 100% duty cycle and a bit lean for comfort.
Photos from my Rover V8 inlet manifold archive.
That’s interesting the injectors could well be the actual reason they leaned off at higher revs and where this perception a bigger plenum space would help. Thanks for the pictures. OEM Hotwire plenum trumpets from landrover and as fitted to many tvrs (top), OEM TVR 500 scaffold pipes (middle) and ACT Carbons:
The 500 trumpet base features enlarged trumpets (45mm iirc) - most other tvr's used largely bone stock 3.9 landrover stuff. Even the 500 had bone stock 3.9 injectors running 100% duty cycle and a bit lean for comfort.
Photos from my Rover V8 inlet manifold archive.
Classic chim, absolutely my reason I'm pi$$ed off with a certain TVR 'specialist' as when my car had a few upgrades I supplied genuine Bosch 'white' injectors. Flow matched to 365ccm. I asked them to fit them and they didn't! They said my car would be over fueled.
My words were they'll be fine if tuned to reduce the duty cycle!!!!!
Just ignored me!! As a result I've now got 8 brand new Bosch injectors sitting in a bag.
One day I'll fit them and get the car mapped PROPERLY!!
Cost me near £400 for a bag of injectors sitting idle.
My words were they'll be fine if tuned to reduce the duty cycle!!!!!
Just ignored me!! As a result I've now got 8 brand new Bosch injectors sitting in a bag.
One day I'll fit them and get the car mapped PROPERLY!!
Cost me near £400 for a bag of injectors sitting idle.
Classic Chim said:
That’s interesting the injectors could well be the actual reason they leaned off at higher revs and where this perception a bigger plenum space would help. Thanks for the pictures.
Don’t follow that logic - if the plenum gave it more air it would go even leaner not richer.The 500 is the only engine that gets the most benefit from induction upgrades, even then it’s a bit pointless doing the trumpets etc if it’s still sucking through the also bone stock air flow meter that’s from the 3.9
you need to do the trumpets, afm delete, distributor delete, injectors and maybe a 72mm plenum if you are getting into the 300’s - your aftermarket ecu will show the wot plenum pressure compared to atmospheric to determine that.
My car has.....
NO AFM.
NO distributor.
NO stepper motor.
Has....coil packs etc.
Carbon trumpets
Act exhaust manifolds.
Act Y pipe..
Kent 885 cam..
Adjustable Vernier cam timing.
That's exactly WHY I strongly suggested and insisted the uprated injectors get put in and mapped accordingly..
I was ignored!!
Told, 'id have to map it twice'.
Twice??!!
Put the Bosch whites in and map it..
Still F'in charged me £1100 to map it on bog stock injectors!!!!!!
NO AFM.
NO distributor.
NO stepper motor.
Has....coil packs etc.
Carbon trumpets
Act exhaust manifolds.
Act Y pipe..
Kent 885 cam..
Adjustable Vernier cam timing.
That's exactly WHY I strongly suggested and insisted the uprated injectors get put in and mapped accordingly..
I was ignored!!
Told, 'id have to map it twice'.
Twice??!!
Put the Bosch whites in and map it..
Still F'in charged me £1100 to map it on bog stock injectors!!!!!!
I would just leave it alone and enjoy it now, you should be experiencing much better throttle response etc on your set up anyway providing its been mapped correctly.
You have done all the good bits so hats off to you, dont know why they wouldnt fit the injectors but normally they know best.
Im doubtful they would make any difference anyway.
You have done all the good bits so hats off to you, dont know why they wouldnt fit the injectors but normally they know best.
Im doubtful they would make any difference anyway.
I can't see the plenum spacer making any difference, caveat : I've never done the exact test back to back, but have seen plenty of cars with them on and they just make the power you expect and the drivability you expect. It won't hurt anything but it's not going to set the performance world alight. Just watch bonnet clearance from the extra height of the plenum now.
The injectors would have been a nice fit, take some advantage of the better misting / mixture presentation. You have per-bank lambdas so you're probably running batch fired injection , so some of the benefit is lost from fuel standing in a stagnant port. I've never ever measured a power boost from fine mist injectors in the rover despite what you might read. But they often improve cold starting, and there *might* be some economy / smoothness benefit but again you're batch fired so some of those benefits are lost.
1100 pounds for mapping ? Even allowing for the tax man's cut that's 900 pounds for the mapper ... was that just mapping or was there other work also done? There's often more to these stories.
The injectors would have been a nice fit, take some advantage of the better misting / mixture presentation. You have per-bank lambdas so you're probably running batch fired injection , so some of the benefit is lost from fuel standing in a stagnant port. I've never ever measured a power boost from fine mist injectors in the rover despite what you might read. But they often improve cold starting, and there *might* be some economy / smoothness benefit but again you're batch fired so some of those benefits are lost.
1100 pounds for mapping ? Even allowing for the tax man's cut that's 900 pounds for the mapper ... was that just mapping or was there other work also done? There's often more to these stories.
spitfire4v8 said:
I can't see the plenum spacer making any difference, caveat : I've never done the exact test back to back, but have seen plenty of cars with them on and they just make the power you expect and the drivability you expect. It won't hurt anything but it's not going to set the performance world alight. Just watch bonnet clearance from the extra height of the plenum now.
The injectors would have been a nice fit, take some advantage of the better misting / mixture presentation. You have per-bank lambdas so you're probably running batch fired injection , so some of the benefit is lost from fuel standing in a stagnant port. I've never ever measured a power boost from fine mist injectors in the rover despite what you might read. But they often improve cold starting, and there *might* be some economy / smoothness benefit but again you're batch fired so some of those benefits are lost.
1100 pounds for mapping ? Even allowing for the tax man's cut that's 900 pounds for the mapper ... was that just mapping or was there other work also done? There's often more to these stories.
I had lots of work done that was itemized. The injectors would have been a nice fit, take some advantage of the better misting / mixture presentation. You have per-bank lambdas so you're probably running batch fired injection , so some of the benefit is lost from fuel standing in a stagnant port. I've never ever measured a power boost from fine mist injectors in the rover despite what you might read. But they often improve cold starting, and there *might* be some economy / smoothness benefit but again you're batch fired so some of those benefits are lost.
1100 pounds for mapping ? Even allowing for the tax man's cut that's 900 pounds for the mapper ... was that just mapping or was there other work also done? There's often more to these stories.
One itemized charge was £875 plus vat specifically for mapping. That 875 was JUST for the mapping.
I was told (hmmmm) my car spent 2 days on the Dyno.
And your comments on the new injectors going in to take advantage of lower impudence and better spray pattern was what I wanted.
Bearing in mind the standard injectors run at 100% and are on the edge of their limits I thought larger flow rate ones with a better pattern turned down a little would be better.
Better economy and smoother etc.
My logic was ignored. (Even after MANY telephone conversations prior to my car going there).
One day I'll fit the new ones and have what I wanted.
Harvy500 said:
My car has.....
NO AFM.
NO distributor.
NO stepper motor.
Has....coil packs etc.
Carbon trumpets
Act exhaust manifolds.
Act Y pipe..
Kent 885 cam..
Adjustable Vernier cam timing.
So you have all the correct stuff imo - you are at the end of reasonable upgrades for that combo I would suggest.NO AFM.
NO distributor.
NO stepper motor.
Has....coil packs etc.
Carbon trumpets
Act exhaust manifolds.
Act Y pipe..
Kent 885 cam..
Adjustable Vernier cam timing.
Do you have the dyno run printout overlaid with the AFR - if it's not going unduly lean, then you may be fine - but as you say, they are typically running at 100% and a friends 500 was in the high 13's flat out, which isn't the end of the world on a n/a car but doesn't leave much on the table.
Edited by eliot on Wednesday 21st February 09:29
2 days on the dyno is a very looooooooooooooooooooooong time, your mapper must have had all sorts of issues to overcome.
Whilst it's true that to truly refine a map takes a long time (manufacturers will spend months .. but they have all sorts of legislation we don't have to bother abaout) you can get a very nice basic map done in a day .. that's usual say 4 or 5 hours on the dyno, a break for lunch, then some on-the-road time targetting smoothness / response etc.
For instance, i had a rally car on the dyno on saturday, engine spec change with heads and cam changed. It was done in 4 hours including a bit of chatting with the owner. Charge was 200 pounds. Now a rally car on a wild cam isn't going to be the last word in refinement, so i didn't spend as long on that aspect as i might normally on a full road car, but it gives you an idea of how much of a problem your car must have been to have needed 2 full days at it!
is it a car with lots of issues do you know? were they trying to map around some physical issues with the engine spec / build? I can't think why anything would need 2 full days on just the mapping unless it's maybe a system/car the mapper had little experience of (in which case you shouldn't be paying for their learning time either ..)
Whilst it's true that to truly refine a map takes a long time (manufacturers will spend months .. but they have all sorts of legislation we don't have to bother abaout) you can get a very nice basic map done in a day .. that's usual say 4 or 5 hours on the dyno, a break for lunch, then some on-the-road time targetting smoothness / response etc.
For instance, i had a rally car on the dyno on saturday, engine spec change with heads and cam changed. It was done in 4 hours including a bit of chatting with the owner. Charge was 200 pounds. Now a rally car on a wild cam isn't going to be the last word in refinement, so i didn't spend as long on that aspect as i might normally on a full road car, but it gives you an idea of how much of a problem your car must have been to have needed 2 full days at it!
is it a car with lots of issues do you know? were they trying to map around some physical issues with the engine spec / build? I can't think why anything would need 2 full days on just the mapping unless it's maybe a system/car the mapper had little experience of (in which case you shouldn't be paying for their learning time either ..)
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