Megane RS250 engine into R26 - using mk3 fuel pump

[Ewan]

I am swapping the engine in my R26 with a RS250 unit retaining the R26 ECU and loom. Should clarify at this point that 'I' means 'I am paying Rentec in Edinburgh'

Ok, so we are keeping the R26 ECU and loom and swapping in the RS250 engine with turbo and the mk3 inlet manifold, fuel rail and injectors.

I know that we should be able to run the RS250 engine with the existing mk2 fuel pump, although it won't offer the rising rate fuel pressure. The question is can we fit the mk3 fuel pump to my car and take advantage of the rising rate rail with the mk2 ECU and loom without a massive headache?

 

[SP33DY]

So today wasn't quite as productive as I'd hoped. I managed the pads and rod but my brother pitched up to do his brakes. Nothing too complicated just front discs and pads, anyway looks like he's melted the dust seals on his calipers on track, but the biggest drama was when we tried to sort out his snapped dip stick.

We had to pull the TB off to remove the dip stick tube, everything was going well until he refitted the TB and snapped the vacuum line off it. Queue loads of swearing and a gash fix to get him home.

I couldn't find my vernier caliper to take the measurements but the FPR fitted to the sender unit is a lot smaller than the usual bosch fpr found on fuel rails. I couldn't see any legible writing on it, also the fuel pump seems to be of a similar size to the walbro I used in the clio. I'm sure I've got a spare pump some where so will look for it to compare.

Hopefully tomorrow I will get some measurements and some photos.

 

[Ewan]

No problem, if I am in the garage tomorrow night I will pop out the 250 reg

 

[SP33DY]

So I still can't find my vernier. So used an old rusty rule.

Pump length total 113mm
Pump body length 76mm
Pump diameter 38mm

FPR length 41mm
FPR diameter 25mm
PN A6H6FE

*Disclaimer theses measurements were taken with a steel rule that is older than me. As such I can't guarantee they are 100% accurate.

 

[SP33DY]

On a side note, the rods used in 250s have tapered small ends. This means my forged rods don't fit the pistons. I've dropped them off at the machine shop today so they will be ready when I get home.

 

[tutuur]

Great effort lads! I'll keep watching, not of too much help atm as i'm busy moving house

 

[SP33DY]

Does anyone know if the 250 uses the same style FPR? I'm doing some digging online but not finding anything useful at the moment.

 

[andybond]

Does anyone know if the 250 uses the same style FPR? I'm doing some digging online but not finding anything useful at the moment.

Style , not sure. Different pressure though IIRC

 

[Ewan]

I will pop out the regulator from my 250 pump tonight and take some pictures. Keep forgetting to do this [emoji854]

 

[tutuur]

I should have a 225 pump somewhere next week, also have the Clio pump on the bench and in possesion of a 250 fpr aswell.

Here's the number off the fpr: 280160691. Not much to find online though, it does say 550kpa on it!

Same problem with the rail fpr, numbers bring up nothing

Edit: seems i have a different regulator than you, bought off a french guy saying it was a 250 fpr

 

[Ewan]

Just to make @SP33DY feel at home, here are pictures of the 250 reg next to a steel rule

 

[SP33DY]

Outstanding effort gents.

So it's safe to say that the two FPRs are different both in size and pressure.

I did a little bit of digging around today and it looks like lexus is250/gs350 run a 85psi in tank fuel pressure regulator the same size as the one fitted in the 225/230 sender. Also the pump looks very similar. I'm tempted to buy a complete lexus sender unit and see what is use able. If I can use the pump its a bonus as the pump is designed to run at that pressure.

It's not 100% though and I've only found a couple of places quoting the pressure. I'm trying to find some official toyota/lexus information.

http://m.autozone.com/fuel-delivery...86_677045_0/?OnetoOne=true&searchText=800-465

EDIT - Also just found this

Lexus Workshop Manuals > IS 250 RWD V6-2.5L (4GR-FSE) (2007) > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pressure > System Information > Specifications > Page 4892

 

[tutuur]

Great effort! It seems the Clio regulator has the same dimensions as the 250 regulator, will confirm that this weekend.

Would be good if you could find an alternative for the 225 one

 

[Ewan]

Actually feel like progress is being made [emoji846] much easier when there a few of us working on this

 

[SP33DY]

The only downside is I'm offshore until the end of Sep. So I'm happy to order a sender unit but it'll be a while untill I can confirm fitment

 

[tutuur]

Non sport Clio 3 vs 250 has exactly the same dimensions. Anybody have a Clio 3 sport sender unit spare to check what the pressure on the reg is?

Non sport is 350kpa so i expect the sport to be the same, although i've read it's 300 but tbh i don't believe that

 

[SP33DY]

I guess that works out well for you Arthur, you can keep the clio sender unit and pop any bosch fixed rate FPR in there. I wonder if the 250 pump fits in the clio sender?

For me and Ewan using R26 units we need t he smaller FPR. I've made an offer on a lexus server unit, only £30 which I think is an acceptable amount to risk.

I'll cost it all up but it'll come in easily cheaper than my clios setup which came out about a £1000.

 

[tutuur]

Yeah easily cheaper than that! I don't get why everyone is so fussed about swirl pots and stuff, intank unit's these days have come a long way!

Look at the oem's bringing out near 400bhp hothatches, don't think they would use swirl pots

 

[SP33DY]

Yeah the reason I went to the extreme is I was having surge issues on track. But in hind sight I could of easily used something much cheaper..... You live a little and learn a lot

 

[SP33DY]

Small update, managed to get a lexus sender unit. Cost £33 in the end. This means it'll be waiting for me when I get home on the 21st so I should be able to update then. Will cobble some adaptor together and use my bike pump to see what pressure the regulator opens at.

 

[Ewan]

Nice, keep us posted on how you get on