Plenum Spacer

[Harvy500]

Classic Chim said:

Result.
You can get a plenum off an old Rangie and a machine shop can chop off as much or as little as you like.
Make your own

Macs car eventually produced something like 570 hp so I reckon he knows his stuff.

V8 developments can do it to mine.

[Belle427]

I would take Eliot up on his offer.
I had to send my first one back from V8D, it was dreadful.
It had broken through into the water passage underneath and they had used what looked like some kind of epoxy to fill it, the throttle plate would bind on it.
It needs to be done properly.

[eliot]

Belle427 said:

I would take Eliot up on his offer.
I had to send my first one back from V8D, it was dreadful.
It had broken through into the water passage underneath and they had used what looked like some kind of epoxy to fill it, the throttle plate would bind on it.
It needs to be done properly.

Most of of them break through to one degree or another unless you are lucky with the casting.
I also used devcon metal expoxy on about 4 of the ones i did.

The last few that I did, I had the water jacket filled by tig welding. I had to pay a pro to do that, because despite being able to tig weld myself I could never get a neat enough job.

I no longer make them because it’s not really worth the hassle doing them and I think all the people that needed one now have one,
You only really need them on the 500 and when you have done all the mods outlined in this thread.

Apart from bragging rights, I think 70mm would be enough and has less chance of breakthrough

Again, with an aftermarket ecu that has a map sensor you can compare the engine off atmospheric pressure with the wot pressure to determine if your induction is a restriction.

[Harvy500]

Cat is now amongst the pigeons.
My car is a 500hc. My car doesn't have a larger throttle body.
Now it seems after reading this it's a hell of a risk having it done. Or, those that can do it won't.
Now what?

[Belle427]

They sent me another which was ok but I had to fight for it tbh which I hate with suppliers.
When they had it back they agreed it was wrong.
The second one was fine though and they are a decent company to deal with.

Edited by Belle427 on Friday 23 February 10:08

[Johno]

I think the challenge of all the mods and forum discussions is what we all know ... Very little hard evidence exists for singular changes, then assessed and then the next change made, assessed all on one engine, to see what happens from stock through to the varying differences. Plus, no two engine are the same and react differently to different mods.

Add in the odd forum horror story/anomalous issue and it's a soup of opinions and limited clarity of hard data.

A pretty common set of mods for a 500 used to be, 72mm throttle, larger (20) AFM, smooth bore induction with a tornado chip. Then aftermarket ECU's started to become more popular, more air meant more fuel, so more injector options were considered etc. Then Megasquirt/Emerald/MBE/Motech and we started ditching AFM's/distributors/coils for coilpacks. Step onto 5.2 builds, multi throttle applications, Wildcat heads and wilder cams as the ECU could tame them. The TVR community is far from the only souls doing this to the venerable Rover V8.

Summary, there's loads of cars out there with 72mm throttle bodies who've not had issues. I haven't with mine.

Perhaps it's worth to enjoy your car for a couple of months and see how it feels, considering the potential options. Then next have the injectors fitted with the 72mm throttle and have the car remapped to those, versus the baseline you have now. Then see how it drives.... rinse and repeat until you have a 5.2 cross bolted, all forged, 8 ITB's with super charger wedged in there

[macdeb]

Belle427 said:

They sent me another which was ok but I had to fight for it tbh which I hate with suppliers.
When they had it back they agreed it was wrong.
The second one was fine though and they are a decent company to deal with.

Edited by Belle427 on Friday 23 February 10:08

[spitfire4v8]

I fitted a 72mm plenum once and after a while the chemical metal started lifting away. Getting a replacement wasn't easy or quick. I do not fit them any more unless the customer supplies it, they take the risk. The gains over a 65mm are small unless you are really chasing the numbers.

[eliot]

Belle427 said:

They sent me another which was ok but I had to fight for it tbh which I hate with suppliers.
When they had it back they agreed it was wrong.
The second one was fine though and they are a decent company to deal with.

Edited by Belle427 on Friday 23 February 10:08

Jesus - I would (and have in the past) scrapped that - in fact i wouldn't even attempt to machine it out, because you can tell from the other wide that it will be too thin.
If you machine them to 70mm you dont run into issues - as at 72mm they also start to break into the idle screw thread as well.

This is minor breakthrough:


You can pre-measure before starting:


You can see in the 12'clock position where it's just broke through:


Good (suitable for machining) look like this:



And for poor castings i get them welded before machining which deals with the problem:

[Harvy500]

I'm told by good authority that due to similar issues when machining it, they're now sleeved.
That's what I was told so don't take my words as gospel truth.

[spitfire4v8]

There are some which are sleeved, but they are horrendously expensive, and lose the vacuum port for the dizzy (not an issue for some such as yourself on aftermarket, but for lucas people it forces you to either re-instate that port yourself, or move to plenum vacuum). All in all really not worth the faff.
Much better to get Eliot to do you a 70mm one if you're determined to go bigger.

[eliot]

spitfire4v8 said:

There are some which are sleeved, but they are horrendously expensive, and lose the vacuum port for the dizzy (not an issue for some such as yourself on aftermarket, but for lucas people it forces you to either re-instate that port yourself, or move to plenum vacuum). All in all really not worth the faff.
Much better to get Eliot to do you a 70mm one if you're determined to go bigger.

I dont do them anymore, so the gems one is the last one ever - but probably more suited to a gems engine, rather than making it work on a hotwire.

[Johno]

Johno said:

Harvy500 said:

Bosch white injectors.
Bosch part number is.....
0208 155 868.
All flow matched to 368ccm. Low impudence.
I bought them from a company in Sweden.
You can buy them for less if they're not bench tested and flow matched.

Thanks Harvy, I shall have a read/investigate.

Hi Harvy

Have you test fitted these to your fuel rail yet? I notice these don't have a top groove, which injectors for our fuel rail have (please step forward anyone who knows better) for the retaining clip?

It is of course debatable if the fuel rail does bolt down, whether the retaining clips are required or not.

[Harvy500]

On my car the fuel rail does bolt down. Looks like (after a quick look) 2 brackets each side.
Not sure if there's a slot in the injectors have the correct slot but simply that the rail is bolted down they should be held in place securely.

[Johno]

Harvy500 said:

On my car the fuel rail does bolt down. Looks like (after a quick look) 2 brackets each side.
Not sure if there's a slot in the injectors have the correct slot but simply that the rail is bolted down they should be held in place securely.

Absolutely it does (should) bolt down with 4 anchor points.

I was digging around looking at potential alternatives as I want a more modern design, which is easiest with a EV6 Bosch type, versus the newer EV14, when the fit, spray patterns etc are less plentiful and whether our engines would benefit from 12 hole injectors becomes a real debate, much as the 4 hole debate has raged previously. Also, many of the EV14 designs don't have the top groove for the retaining clip.

From my research, Bosch EV6CL are best suited and then its down to which flow rate is best for your given application.

If you can run 3 bar pressure and have aftermarket ECU to change injector duration/dwell times etc. then it's a case of looking or the nearest 'best fit' which is available.

The 'available' part is difficult. There's a few around which are V spray pattern and less of the more suitable conical spray pattern (depending on flow rates) and your view of 'suitable spray pattern'. V or 2 spray patterns appear to be more for 4 valve heads etc ...

So, then I was looking for correlating their fitting to the rail without changes as well as spray pattern etc. I know some of the aftermarket suppliers for RV8 suitable injectors have the bodies machined to enable the fitting of the retaining clip, so I was looking to avoid doing that.

I've ended up with an alternative which is slightly less flow than yours, but still over sized for the requirements. But, it's EV6CL, long type, high impedance, 4 hole, conical spray, Jetronic port (I did look at Uscar to Jetronic adapters) and it has the top retaining clip groove as well.

Bosch 0 280 155 759 & available from Autodoc, new - These are not an upgrade to replace old Lucas ones (you must have aftermarket ECU) for anyone thinking that, I'd be replacing the Siemens Red Top's with a flow rate of 250cc, as they're 2 hole and 12yrs in my application (310+).

Ideally though I'd have something with a lower flow rate, which exist, but aren't available new, or not at least easily.

Such as the Bosch 0 280 155 931 - but these don't always appear to have the top retaining clip groove either, but have a lower & more comparable flow rate @ 260cc .... Have seen two images, one with the top groove and one without.

Choices, choices .... Either way, it's going to Emerald end of the month, so may see if after we've got the new set up dialled in, we can play with different injectors as well.

Edited by Johno on Monday 11th March 13:29

[Sardonicus]

Eliot done mine in around 2016 I had the base/heater void welded up then sent onto him to be bored out with the bigger butterfly , top job Im using Bosch BMW V8 injectors @ 3 BAR think these are around 260/280cc IIRC

Edited by Sardonicus on Thursday 4th April 15:06

[Johno]

Do you know which ones Sardonicus? Injectors?

My Bosch 0 280 150 945, 4 hole disc injectors (they’re not Siemens, got confused) are from when I redid the ECU in 2008, they’re 310cc at 3 bar. They just delivered 318/337 at Emeralds road last week, so not struggling, but given they’re 16yrs old I’m intrigued whether newer ones would improve performance, not in absolute power terms, but efficiency etc.

310cc is over size really, but they’ve worked out well for a long time and whilst I don’t wanna change for changes sake I’m intrigued to look at options.

Edited by Johno on Thursday 4th April 21:37

[Johno]

Harvy500 said:

On my car the fuel rail does bolt down. Looks like (after a quick look) 2 brackets each side.
Not sure if there's a slot in the injectors have the correct slot but simply that the rail is bolted down they should be held in place securely.

Hi Harvy, having done more research on this there’s lots of discussion about why the higher groove etc. some have 1 or some have 2 grooves, some restrict the orientation and some don’t etc.

One engine builder I respect enormously for his depth of knowledge and phenomenal engine he built me and 100’s of other tells me they’re there to not only provide security of fitment, but to ensure they’re the correct height in the inlet tract as well. Orientation also comes into this when using V pattern injectors, more suited for multivalve heads etc.

I’ve seen it argued they’re only fitted so they don’t fall out on the factory build line when being carried around

[Toma500]

Put my early preserp 500 into powers for an mbe ecu upgrade a long time ago now ,also had them check over the cam i suspected it was worn so they also fitted an 885 ,love the change it made lots of useable power / torque linear delivery so much smoother to drive powers also fitted a plenum spacer so they must think they give some benefit , plenum standard apart from spacer standard injectors but flow matched . Dont know how long on rollers for mapping but mapped on standard 95 ron fuel .
Sorry about it being upside down double click it goes correct looks like it was 8 yrs ago wow how time flies

Edited by Toma500 on Friday 5th April 17:05

Edited by Toma500 on Friday 5th April 17:06

[eliot]

Toma500 said:

Put my early preserp 500 into powers for an mbe ecu upgrade a long time ago now ,also had them check over the cam i suspected it was worn so they also fitted an 885 ,love the change it made lots of useable power / torque linear delivery so much smoother to drive powers also fitted a plenum spacer so they must think they give some benefit , plenum standard apart from spacer standard injectors but flow matched . Dont know how long on rollers for mapping but mapped on standard 95 ron fuel .
Sorry about it being upside down double click it goes correct looks like it was 8 yrs ago wow how time flies

Edited by Toma500 on Friday 5th April 17:05

Edited by Toma500 on Friday 5th April 17:06

nice graph - afr about 13 - which I believe is all the standard ones have to give at that level of power.