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K24 7400 installation in S2 3B

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  • K24 7400 installation in S2 3B

    Alright gents,

    Following on from my recent Volvo K24 7400 installation in my 3B S2, here is some info and pics of how i went about the conversion.

    Firstly i purchased a second hand turbo several years ago, which sat in a cupboard until such time that i was ready to get my head round making it fit neatly, with a reasonable OEM look.

    On removing the compressor housing a couple of months back i noticed there was damage to the compressor wheel, serves me right for not checking it out properly when i first bought it.

    Anyhow, i choose Turbo Technics for the refurbishment and off it went.

    £600 later the turbo returned with a billet compressor wheel, uprated 360 Deg bearing and uprated seal pack.

    The exhaust housing i also purchased a few years back as the standard Volvo one is of no use in this application.

    The exhaust housing was fitted to the car along with the CHRA and then the compressor housing fitted to see what mods were needed to it.

    Stock 3B oil and coolant lines fitted the turbo with relative ease to be fair.

    These turbos come with two different compressor housings, a short stubby one with a "V" band fitting and a longer one where the compressor outlet kind of bends rearwards away from the housing.

    By chance i purchased the one with the "V band" outlet which turned out to be good luck as it needed very little fettling to make it fit.

    Also, due to the very limited space between the compressor inlet and the bonnet catch stay directly beside the drivers headlight, i only had space to fit a 2.5" Cobra head.

    In order for the 2.5" Cobra head hose to fit the compressor inlet flange i had to get it machined from 2.75" to 2.5", at the same time this was being done the "V" band connection was machined off and made suitable for a hose to fit on.

    The compressor housing utilises an internal bypass valve which is not the best design. It could be used if you so choose but i preferred to opt for the more reliable S2 stock setup. Blanking plugs are available to block off the port, i'll add the link further down. ( Still waiting on mine to arrive from the states!)

    So, with the compressor housing machined it was fitted to the turbo, then i set about making the cobra head hose fit. I loosened the gearbox and engine mounts and moved the engine as far back as i could to gain a little more space. With the hose fitted to the turbo it was rubbing the bonnet catch stay, it you look at this stay there is a small bit that can be filed down do give a little more clearance. every mm counts here as it is so tight. I'm still not 100% happy with it but certainly good enough for now.

    I purchased a 1" take off fitting which fits on to the Cobra head hose, this allows the DV to recirculate back to the intake. Again i'll add the link for this further down.

    I reused the 3B Turbo to intercooler hose, and with a bit of trimming it worked a treat. I also had to order a 45 deg silicone hose and 2" aluminium joiner to complete the turbo outlet to RS2 intercooler hose. So glad i kept the 3B hose after my RS2 conversion last year!

    All that was left now was to find a way of connecting the airbox to the Coba head hose.

    A 2.5" stainless tight radius elbow was purchased for this and also a silicone reducer to go from the MAF size down to the 2.5" elbow. A small stainless tube was welded on to the side of the elbow to allow the N75 to bleed back.

    And that's about it, now that i have completed the conversion i can say it was not too bad. There was a bit of head scratching to find the right Cobra head as the 3" one i bought first of all was just too big, the space between the compressor inlet and bonnet catch would not allow fitment of it. Also plumbing in the DV valve and MAF to Cobra head was a bit of a chew but got there in the end.

    Here are links for the materials purchased to make the conversion work.

    2.5" Cobra head http://www.do88.co.uk/product_info.p...0de1970529b413

    1" take off for DV https://www.ebay.co.uk/itm/Revotec-2...72.m2749.l2649

    2" aluminium joiner https://www.ebay.co.uk/itm/Aluminium...72.m2749.l2649

    45 Deg silicone hose https://www.ebay.co.uk/itm/Ramair-45...72.m2749.l2649

    MAF to Cobra head elbow https://www.ebay.co.uk/itm/Silicone-...72.m2749.l2649

    Compressor housing blanking plate http://www.vivaperformance.com/cbv-b...r-v70r-s60-t5/

    Prob missed some detail but that's enough typing for now.







    Inlet machined from 2.75" to 2.5" "V" band machined off and lip left for hose to secure over "V" band machined off and lip left for hose to secure over Porous material, notice small section i had to file down on lip due to it looking like it could fall off be sucked through compressor
    Last edited by gmac78; 21st June 2018, 09:38.

  • #2
    20180320_191459.jpg Here is a pic of how close the boost reference line is to the oil supply pipe once everything is clocked to work. There's about 0.5-1mm clearance which is just enough as the oil supply pipe is pretty rigid with very little flex. The fitting could be filed down slightly to give more clearance if required. If you push the oil supply pipe against the fitting it simply returns to this position once you take pressure of it. Also the brass fitting on the turbo is slightly too long, so when you fit the hose on it comes up tight against the back of the Cobra head at a tight 90deg angle, possibly restricting flow/pressure to N75. I simply cut it back 10mm or so and flared the end to ensure the hose doesn't pop off, this gives enough clearance for the reference line to have a more gradual bend off the fitting. A different type of fitting could be bought for this if not happy with the routing off the reference line to N75.
    Last edited by gmac78; 21st June 2018, 10:06.

    Comment


    • #3
      Thanks for sharing useful photos. There is also an option if you don't want to use stock Volvo internal bypass: old audi K24 or K26 compressor housing can be machined to work with 7400 compressor wheel. In this case the turbo will look just like stock audi one. But Volvo 7400 compressor housing may have a better design in terms of effectiveness.

      Comment


      • #4
        Big thanks for sharing all the info and links you have with us and a big well done for going ahead with it!! I'm anticipating your waste gate plug arrival with serious interest to know the outcome.

        Do you have any pics of the Turbo technics supplied Billet wheel as it was fitted to the cold side? I'm just interested in doing thew same as you and would like to know the latest on billet wheels for these Volvo 7400 turbos?
        96 URS6 plus speck saloon
        96 URS6 plus speck estate
        94 2.6 80 Avant
        99 2.8 final edition Cabriolet

        Comment


        • #5
          Originally posted by _ShurikeN View Post
          Thanks for sharing useful photos. There is also an option if you don't want to use stock Volvo internal bypass: old audi K24 or K26 compressor housing can be machined to work with 7400 compressor wheel. In this case the turbo will look just like stock audi one. But Volvo 7400 compressor housing may have a better design in terms of effectiveness.
          K26 #6 can be used but not that great as the machined k24

          https://www.flickr.com/photos/quattr...57664930622196
          sigpic

          Comment


          • #6
            Nice job!
            I was meaning
            Originally posted by _ShurikeN View Post
            compressor housing
            also.

            Comment


            • #7
              Originally posted by varia View Post

              K26 #6 can be used but not that great as the machined k24

              https://www.flickr.com/photos/quattr...57664930622196
              Whats the reason for that?
              96 URS6 plus speck saloon
              96 URS6 plus speck estate
              94 2.6 80 Avant
              99 2.8 final edition Cabriolet

              Comment


              • #8
                Vorsprung- Did you see the pics of the billet wheel at the start of this post. Basically a replacement OEM compressor wheel was not available which is why i went down the road of a billet version. I asked them to weigh the original and compare against the billet, the billet was 4g less if memory serves me. Not sure how much of a difference that would make to spool but it comes on quick, very responsive compared to the RS2 turbo. However i would have been running a tooth on the timing when i had the RS2 turbo installed so a bit annoyed i didn't sample it with the engine running properly. Easy enough to fit again if i feel the need.

                Turbo Technics gave me the name of the company they use to supply these billet wheels, for the life of me i can't rem what they were called now. An American company i think. Is the turbo you have damaged?

                Comment


                • #9
                  I could see the cold side originally and after your comment above went back to see the +19 photos. All good cheers and great photos. If it weighs 4 grams less i would suspect it's worthwhile as it could be a 10% improvement over the stock wheel if you do the math. I wonder what the original one weighs? Be good to know, however if your going to do this you might as well do it right the once and be done with it so i'll be doing exactly the same as you by the looks of it.

                  Well i bought mine of Andy10v so i'd seriously doubt it's damaged, tbh, but like you i haven't checked but i was always of the opinion that i would go for a 360 bearing for longevity and a billet wheel so wasn't bothered really. I'm just wondering now why varia says a machined K24 hotside is better than a Porsche K26/6 ?

                  I thought about the RS2 turbo but it just doesn't suite what i'm after hence why i bought the K24 7400. That price you mentioned was that £600 all in inc the wheel?
                  96 URS6 plus speck saloon
                  96 URS6 plus speck estate
                  94 2.6 80 Avant
                  99 2.8 final edition Cabriolet

                  Comment


                  • #10
                    Yeh it was around the £600, infact it was cheaper than that slightly, i think £580ish but that was for everything including delivery.

                    Just looked back through my emails from them, here are the two pricings

                    1. Standard rebuild- We can repair with billet and standard bearings and seals for £400 + vat plus shipping

                    2. Upgraded rebuild- We can repair the unit with a Billet wheel, competition bearings and seals, 360 thrust bearing.

                    £450 + Vat, plus £30 + Vat carriage

                    All their Hybrid, performance and modified turbos do not have a warranty but this seems to be the norm looking at other Turbo companies.

                    I spoke to a technician who does the rebuilds and when i mentioned that the chips i have were rated for around 1.7bar he strongly suggested i opt for upgraded option. Very little difference in price really so a no brainer.

                    It's amazing how quiet a newly refurbed turbo sounds, very little whistling compared to other turbos i've heard!

                    In your application the engine bay will be more spacious so may very well get off with a different intake setup.

                    I've still got a 3" Cobra head if you want to try that when the time comes?

                    Cheers

                    Comment


                    • #11


                      Thanks for the pricing and general info it's much appreciated, i'm very tempted to just go ahead and get mine done although what's holding me back is uncertainty of the hotside for now. I'll be going for a custom 3" down pipe to keep egt in check so by the time it gets finished the wallet will be hurting. Still if i get the 7400 part of it done i'll be a step closer and hearing how you get on will make a big difference! Thanks for the offer of the Cobra head, when the time comes i'll let you know. Cheers Mark.
                      96 URS6 plus speck saloon
                      96 URS6 plus speck estate
                      94 2.6 80 Avant
                      99 2.8 final edition Cabriolet

                      Comment


                      • #12
                        What hotside did you get?

                        Comment


                        • #13
                          I've got the Porsche K26 / 6.
                          96 URS6 plus speck saloon
                          96 URS6 plus speck estate
                          94 2.6 80 Avant
                          99 2.8 final edition Cabriolet

                          Comment


                          • #14
                            I can't actually remember what hotside i bought now it's been so long, i'd need to get the part numbers. Do you think that's the correct one? I remember Andy buying a hotside that was too big, have you tried it on the turbo for fitment?

                            Comment


                            • #15
                              Originally posted by Vorsprung durch Technik View Post
                              I could see the cold side originally and after your comment above went back to see the +19 photos. All good cheers and great photos. If it weighs 4 grams less i would suspect it's worthwhile as it could be a 10% improvement over the stock wheel if you do the math. I wonder what the original one weighs? Be good to know, however if your going to do this you might as well do it right the once and be done with it so i'll be doing exactly the same as you by the looks of it.

                              Well i bought mine of Andy10v so i'd seriously doubt it's damaged, tbh, but like you i haven't checked but i was always of the opinion that i would go for a 360 bearing for longevity and a billet wheel so wasn't bothered really. I'm just wondering now why varia says a machined K24 hotside is better than a Porsche K26/6 ?

                              I thought about the RS2 turbo but it just doesn't suite what i'm after hence why i bought the K24 7400. That price you mentioned was that £600 all in inc the wheel?

                              David (hybrid_hatch or Ruffiano)
                              https://www.s2forum.com/forum/techni...di-application


                              Who actually pioneered this volvo turbo thing with Hank's help.
                              " it was my car that had them both. the 26/6 doesn't perfectly match the profile of the 7400 turbine, it matches it at the end, but not throughout. machining a k24 to match it perfectly means it is more efficient, its not letting extra air through without taking the force from it"
                              sigpic

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