Big Uno's R26 Project / Engine Build

Discussion in 'Megane Projects' started by Big Uno, Oct 28, 2017.

  1. Gavin.

    Gavin. RSM Admin

    @JamesBryan just told me about this, some impressive figures there!
    Big Uno likes this.
  2. Absolutely mega mate.

    As Chris said, with a bit lower compression and cams it could be on its way to 500bhp if you decided to chase the figures.
    Gavin., Big Uno and Si271 like this.
  3. Awesome result Karl, bet your well happy with that!
    What sort of gain do you think you’ll get from changing the cams? If it’s 20bhp my power guess was spot on :tearsofjoy:
    Big Uno likes this.
  4. Well done mate!!! Cracking result! Very pleased for you. I'm sure it makes all the hard work and pain worth it now! I salute you sir!

    Sent from my Pixel XL using Tapatalk
    Big Uno likes this.
  5. Big Uno

    Big Uno RSM Trader

    Thank you guys!!!

    We did talk about cam gains, if you can potentially add the effective of 20hp to the power as the engine where naturally aspirated it will be that plus that multiplied by that by bar (boost)
    So in theory if I could raise its power by 20hp I would gain around 50hp @ 1.5bar.
    So even a small gain from cams can be a larger gain at the top end, with a likely sacrifice to bottom end power and spooling time.

    Yes I am really happy, will be looking at putting a larger fuel pump in the tank next I think. But having now mashed the throttle a bit I dont think I will be bored of the power... until winter anyway :smilingimp:
    Mikey4410 likes this.
  6. ianplymouth

    ianplymouth RSM Club Member

    great stuff Karl, glad you are happy with the results of your hard work over the last year, (almost) now i cant wait till Monday night :laughing::laughing::sunglasses::sunglasses:
    Big Uno likes this.
  7. Big Uno

    Big Uno RSM Trader

    Bring a lid, and spare pair of pants :tearsofjoy:
  8. ianplymouth

    ianplymouth RSM Club Member

    Will do, you got yours ready :laughing::laughing:
    Big Uno likes this.
  9. Big Uno

    Big Uno RSM Trader

    Were not doing the Rugby gp dont get any ideas :tearsofjoy::tearsofjoy:
    ianplymouth likes this.
  10. ianplymouth

    ianplymouth RSM Club Member

    Wanna bet :laughing::laughing::laughing::laughing::laughing:
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  11. Wowzers !!!!! Dam man thats epic
    Big Uno likes this.
  12. I am glad everything went well with the mapping and those are some great figures and a nice graph. It has been a very impressive build and I like the attention to detail. I have the same pump as you after the swirl pot and a walbro in tank pump, no idea how it runs though as they are still sitting on the workbench!
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  13. It even ran 330bhp on gate pressure with fueling running rich as fuck to start with!
    Mikey4410 likes this.
  14. I should imagine that feels fairly potent!
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  15. Big Uno

    Big Uno RSM Trader

    I seem to be playing a game of musical regulator recently, anyway here is where it is now fitted :tearsofjoy:

    Had some fairly large changes to the fuel system since the car was mapped.

    Since we woke the turbo up engine bay temperatures have been ripping and so have fuel temperatures too...
    After a fairly short time of giving it some boost it was quite apparent something would need to be done... at times even misfiring on load due to what I believe to be vaporised fuel in the lines.

    One of the fundemental problems with the Megane fuel system is where the lines run, as you have seen I have fitted a rail return, but both lines run in the original place... behind the turbo...
    I think its fairly expected the engine would get hot, and with my tubular manifold and collector that sits right infront of the fuel lines and seperated only by the OE heatshield, heat transfer was way too high.
    I have been considering cooling the fuel but first I think its more important to remove the hot spots and fix the issue instead of masking it.

    So I have ripped out both fuel lines completely, and moved everything over to the cooler side of the bay, I was hoping to run the lines below the car as they where, but crossing the exhaust was a problem, and there was no nice way to swap sides.
    My lines now run through the car and up through the bulkhead. Really wanted to avoid running the lines internally, afterall it is a road going car, and the lines below helps with cooling. But this is the best solution for now I think.

    The engine running seems to now be completely fixed and the fuel is massively cooler.

    The next problem I seem to be having is the rear gear linkage is coming off, seems to be due to heat. It is the rear outer retainer part that fixes to the U shape bracket on the box. The white retaining pin seems to have lost its spring and doesnt retain for long :tearsofjoy: fairly sure this may be due to heat.
    Has anyone got any fixes for this?

  16. Big Uno

    Big Uno RSM Trader

    Unfortunately I have had to decide on selling the car, I have had a lot of good and bad times building it, and hope to carry on with another at a later date.

    I have posted a quick sale thread up here;£13k-o-n-o.17208/

    Really hope if a sale does go through it will be to an enthusiast here.

    For now I will still be continuing work on the car, and still be posting progress! I want it to be in its best possible shape for a sale and there are still some areas that need my attention :tongueout:
  17. Noooooooooooooo!
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  18. Big Uno

    Big Uno RSM Trader

    Needs must unfortunately mate :blush:
  19. Very sad to see this happen mate :worried:

    Although.... if you do decide to break it, get in touch?
    Big Uno likes this.
  20. Big Uno

    Big Uno RSM Trader

    Depends what you want? Engine, gearbox and turbo? :tearsofjoy: car comes free.
    Gray and Ian Hughes like this.
  21. Big Uno

    Big Uno RSM Trader

    Small update, not had much spare time for car stuff over the last few weeks, but have made a few small changes.

    Quite soon following mapping, I had some issues with ignition, as I mentioned before there was missfiring at high rpm on load.
    This has now been fixed by a simple coil pack change. Now running Valeo green tops and had no problems whatsoever. The other ones seem to have been damaged by the heat, sometimes you get what you pay for :smile:
    All 4 coil pack retaining bolts are now helicoiled too.

    I have also fitted a turbo blanket, this has dropped engine bay temps dramatically! Doesnt look great, but it does work well.


    I also had a request for some data on the cars drivability. But thought I would post it up as I am sure others might be interested too.

    The first video is from a standstill, and shows the pull on WOT from around 3500rpm in second and through third.
    Struggling to get the power on the floor at the top end of second, some wider and better tyres would help.

    Second video shows a couple of different pulls, different rpm ranges in different gears.

    Both videos taken on private circuit... of course.

    Thought I would include intake temperature, ambient was varying between 18 - 20 centrigrade where I was driving. It shows how well the intercooler is working.

    There is also fairly minimal lag from the G25, you will see it holds well above 3500rpm. The Turbosmart gen5 is also doing a great job at maintaining pressure.

    As you can see the difference between a stock or stage 1 engine to this are quite large :tearsofjoy: it is a handful. Did get into 5th at low rpm towards the end of the video but I think its second, third and fourth people want to see. By the redline in 4th you are already getting a serious lick on at around 130mph.
    ianplymouth likes this.
  22. Thank you for the drivability data.I would say that it has a huge advantage in transient responce.Below is my videos would love to hear what you think and how you compare the spool.Mine is gtx3071 genII on 0.63 housing.

    Big Uno likes this.
  23. Big Uno

    Big Uno RSM Trader

    Yes there is no doubt the G25 spool time is considerably faster, would be interesting if we both did some pulls from say the same rpm at full throttle in the same gear?
    I think at higher rpm the 3071 will be almost as responsive. It looks like the 25 output is also considerably higher at lower rpm too. Its quite interesting, I would say the stats given by Garrett are correct.

    What power are you making now? And what cams & compression are you running?

    My limiter is my cams, but I dont think 430 is bad with stock cams at 1.5bar, I dont see a need to run higher boost than what I am as the turbo is currently efficient and I wouldnt want to drop my compression. I think with some more duration and overlap mine could see 470+ at the same boost.
  24. Power is around 490-500 at 1.9 bar limited with small exhaust hausing.
    Compresion is 9:1 and 401 catcams.
    Yes for sure you are limited with cams.
    And I agree that g25 is making more power lower down and for sure is a lot more responsive.
    Yes we can start from 2k rpm full throtle in 3th and than in4th.
  25. Big Uno

    Big Uno RSM Trader

    Thats enough power I think you would benifit most from more lower end power if you can keep the top end the same. Do you have graphs from power runs would be interesting to see the two turbos compared.

    I can see about doing some pulls tomorrow for you!
  26. dyno R26r.jpg Great work! Read your thread. Excellent workmanship and congratulations! I too am running 438hp and Chris did my tune as well. I have a different turbo a GTX Garrett 3076r with upgraded BB Garrett core assembly. This is my dyno done about a couple of months earlier to you. I did see you are making your torque earlier than mine-about 1000 rpms- but final figures are about the same. It is a handful as I found out at Donnington but car really flys! I just added a Gripper diff to help on track!
    Big Uno likes this.
  27. Big Uno

    Big Uno RSM Trader

    Great stuff stradman, yes I am making power and torque considerably sooner, I re-attached both our graphs below to show the differences more clearly.
    The main difference here is the spooling time, mine is around 1000rpm sooner, of course giving the early power delivery. Although your power is being delivered very well going by the graph. This is really interesting comparing data.

    I would imagine Chris limited your torque, I asked to keep mine down, as I like the gearbox working the way it is :tearsofjoy: although my clutch is rated for more than the 360ftlb I am running.

    I am guessing given the figures we have a very similar set up other than the turbo? 870cc injectors, stock cams, stock compression? I would be interested to see your setup, what wastegate are you using also? Did he give you a boost plot? I suspect you are running slightly more boost than me, around 10% more?

    dyno R26r.jpg
  28. Hi BigUno, here is the boost plot.
    I am running Catcams and a Forge wastegate. My car is setup for track use primarily so its working high up the rev range by and large and so the lower down torque is not quite as important to me I guess but will see how the season transpires! Here is my one and only so far track day at Donington. This was running 390hp just before Chris tuned it. This was one of the reasons I decided to get the Gripper diff.
    AFR Boost.jpg
    Big Uno likes this.
  29. Big Uno

    Big Uno RSM Trader

    Really quite low boost, was expecting stock cams with the power figure as close to mine :tearsofjoy: I am guessing you could make more power if you wanted! do you find you are also coming off boost around tighter tracks often? Looks like it is doing ok at Donnington but that is quite fast as a car track. Sounds like it goes well :smile:
  30. How is the car doing in the meantime?
  31. ianplymouth

    ianplymouth RSM Club Member

    I had a passenger lap in it at Abingdon, goes really well :laughing: he has a boost monitor fitted and it said it was going into over boost, but when we came back in it was still showing minimal boost on tick over, instead of a vacuum, so i really think his boost gauge and sensor is not working properly, not sure if he has sorted it yet.
    Big Uno likes this.
  32. Just read this start to finish, I'm guessing by the last post the car is still around.

    @Big Uno Still tracking it?
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  33. ianplymouth

    ianplymouth RSM Club Member

    No Big uno doesn't track it, he sold it to a guy called Simon, he does track it and it's quick :laughing::laughing::laughing:
    Big Uno likes this.
  34. matt e

    matt e South East RSM Area Rep

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  35. Big Uno

    Big Uno RSM Trader

    Hey fellas, sorry for the inactivity! Ians right, and matt put in a link above to Simons follow on thread!

    Hope you are doing OK Ian? How did you find the Megane?? Did tell you its goes well! :sunglasses:
  36. ianplymouth

    ianplymouth RSM Club Member

    Im doing okay how about you, moved onto a mk3 265 and enjoying it, off to the ring on the 20th can't wait.

    It was very nice as a passenger, pulled very well with no neck ripping jerk, just solid pull all the way to the red line, that was until the boost gauge showed an overboost, but 100% sure it's the gauge sensor that's faulty.
  37. Hello partner, I am preparing to build my engine, since it is somewhat tired of time.
    I have led his entire post with great enthusiasm. but there are things that I don't quite understand my English.

    You use this internal configuration:

    Block flanged at 83 mm.
    Wossner Pistons 83mm.
    PEC cranks.
    Oil pump, original renault gasket kit distribution.
    Supertech induction nitrile steel valves / inconel exhaust.

    but you don't change camshafts and keep as standard?
  38. ianplymouth

    ianplymouth RSM Club Member

    Block flanged, not sure he did it but i think he was going to machine a groove in the top of the liner to put copper rings in.

    Standard bore is 82.7mm, 83mm pistons will would give a used engine the opportunity to be bored out or honed to give a "as new" engine build.

    PEC cranks, not sure but he used PEC conrods, H beams are the ones to go for, H ones are for torque.

    I would change the oil pump and chain if the engine is going to be rebuilt, would be a shame to all the other work and have the pump or the chain to break.

    The standard valves are okay, but i had one let go on track, the standard valves are two piece, the Supertec valves are one piece, would also put better valve springs in as well, you don't need double ones either and as long as you don't fit Catcams etc, as for the cams, you don't really need them unless you want to go silly on power, standard cams are good for 450hp +, bit of waste of money in my opinion.
  39. ianplymouth

    ianplymouth RSM Club Member

    Is it the pressure relief valve that your after ???

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