Nems NA to TT conversion, with an added suprise ;)

Discussion in 'Member's Garage' started by SRB-2NV, Jan 22, 2014.

  1. SRB-2NV


    Ok well the whole exhaust side is going to be re done. Currently the 2.5" twin exhaust merging into a single 3" is just far too big for the power i want even in a compound setup. Just for an example i'm after roughly 400-450kw total in my setup or enough to run a 10.99 at the drags.

    Nuggetgarage on youtube have a rearmount turbo VH45 supra with a GT4788 making ~1000rwhp on twin 2" pipes and run low 9s.

    This car does 8.1 @ 170mph and makes ~1200hp with twin 2.25" pipes to a single turbo...

    Basically the piping size i have on the car at the moment is capable of like ~1500hp .

    I'm going to go get my front pipes remade in 2" stainless steel and wrap them to see how much of a difference is made. If the difference in spool is noticeable i'll re-do the entire setup to twin 2" to single 2.5" and tuck the intercooler pipe up so its not hanging close to the ground.

    Another interesting thing to note is charge piping doesnt seem to have to be as large either with a few cars i've found doing ~750rwhp on 2.25" charge piping. I'll be keeping mine 2.5" but i will step it down to 2-2.25 next to the radiator as i want to put the factory radiator and fan back into the car, the Honda stuff is just not cutting it.

    I got it all that wrong but i still got the turbo on full boost at 4500.
    IB likes this.
  2. SRB-2NV


    Heres a bit more proof i went overboard. This car below is 6.6L with an 88mm GTX47 using twin 2.5" to single 3". Probably 1500hp+


    Shows the compound system works... i spooled a 1000HP GT42R on this size piping with a 3L.
  3. SRB-2NV


    Also seems the factory radiator idea is a no go. Cant route the charge piping anywhere without causing the same issues i have now. I sourced a V mount radiator kit that i should hopefully be picking up in a few days.
  4. SRB-2NV


    V mount radiator kit is here. 20220108_152025.jpg
    Harts likes this.
  5. rob260

    rob260 Administrator Staff Member

    Looks interesting what did you use?
  6. SRB-2NV


    Its a second hand but never used CXracing kit.
  7. SRB-2NV


    Ok well guys, the rearmount is being taken off and the car is getting the exhaust re fitted. It was a good run and the system works, it just doesn't work as well as i'd like. The car definately makes more power but since the stock turbos have to breathe through the rearmount its pretty much the same as having upgraded turbos fitted. For the system to work how i want it, i'd have to mount everything up front or remove the stock turbos and do it all rear mounted.

    Between that and my fabricator moving 3 hours away im also over the police attention the car gets. Realistically i'll just refit the nitrous kit and get it tuned again.
  8. SRB-2NV


    Some carbon dipped interior bits
  9. SRB-2NV


    Well, car has sat for the last year and i haven't done anything to it apart from add some carbon bits and a new steering wheel from RGS.

    There are many things i want to test and thing i will be doing is removing the springs from the front turbos external gates to get more wastegate energy to the rearmount, earlier. As before those WG added into the dumps give a SC like boost curve and only open fairly late which would hurt big turbo spool due to less exhaust energy.

    If the rearmount spools quicker like that i will be removing the Vband 0.83 housing and putting the 1.01A/R back on. If not, i'll put a T4 divided 0.63A/R housing onto it and re-employ my quickspool valve.

    if i were to re-do this setup from day one, i'd do the following:
    Factory front half of NA exhaust(2.0"), Y to single 2.25" after the cats. All heat wrapped.
    Two 40mm wastegates in the front pipes.
    Intercooler pipe to the front 2.5" Oval piping for ground clearance.
    Volvo Penta 3581019 one way valve in the (now metal)intake T piece to allow the stock turbos to breath as factory till the rearmount makes boost.
    Quickspool valve and 1.21A/R housing.

    The mistake i made was going too big on the exhaust side, basically my rearmount exhaust piping is sized for something making 1200hp. Going to smaller housings to fight that isn't ideal. A smaller pipe, with enough wastegate and a big housing will make all the power most people will need as the smallest point of the exhaust is now the rearmounts turbine inlet, going bigger than that won't do anything but add lag.
  10. SRB-2NV


    Ok well got a few more bits.

    Bought a HDi EBC to control the stock turbos, as the Eboost2 will be for the GTX3584RS.

    Got more heat wrap for the exhaust and a Pulsar 60mm wastegate to replace the Ebay 60mm. Also got a T51R compressor housing because everyone likes super loud spool noises.

    I honestly haven't decided whether to go for a different exhaust housing yet. I'm thinking that going to small will restrict me regardless of my oversize piping and maybe it should stay as is. Best course of action would be to get the piping remade but it's a pain in the neck.

    Currently, the 11-12psi springs in the stock turbos and 7-8psi spring in the gtx give me 20psi total boost. The plan is to up the spring in the big turbo to 12-14psi and LOWER the spring pressure in the stockers to ~5-6psi. This will give me the same total of 20psi minimum but with the big, more efficient turbo doing more of the work. Then i can up either turbos boost to whatever i need.
    rob260 likes this.
  11. SRB-2NV


    NI85 likes this.
  12. SRB-2NV


    Also got a T4 0.63 housing to try, but i'm thinking it will be way too small. It was a second hand one so atleast it didnt cost much.
  13. SRB-2NV


    Second EBC is here, just waiting on the T51R compressor housing to arrive. 20230206_173559.jpg
  14. SRB-2NV


  15. SRB-2NV


    New housings are on. Put the 1.01 exhaust housing back on and the T51R comp housing

    Attached Files:

  16. SRB-2NV


    Big changes coming to the whole setup soon, i won't post any further pictures or information till its done.
    lidz likes this.

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