twins to single / 95 octane+meth: advice

seb.apprenti

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Nov 28, 2018
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Hi friends .
following a problem with my twins, I am considering switching to a single turbo.
regarding power, I would like a power close to or slightly exceeding 600 whp because my block is in stock at the moment. (I know that I am taking a risk despite everything)
my fuel is 95 oct (eur) with 1600 cc 100% meth (6 nozzles on the intake manifold, and one nozzle in the charge pipe).
I'm thinking of going for a speedtech top mount kit (I sent them an email and got a quick response and I really appreciated it)
The complicated part for me is the choice of turbo.
It's a nice street car, I'm not looking to break a record.
I don't need a water-cooled turbo.
I think Precision would be a good choice...but which one to choose?
6266?6466? bigger ?
which A/R
I would like it to remain responsive.
the graphics on the speedtech site are for the e85.
you must multiply by 0.70 for 93 oct and again subtract 15 to 20% for whp.
but with the amount of meth I spray, what do I choose?
I tried searching the forum, but I didn't really find an answer to my question.
thank you to those who take the time to read and respond to me
 

JohnDaviz

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Jan 6, 2019
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you are the first ever i heard who has issues with hydra turbos. Sucks Mate.

Besides your fueling pump and meth...
What do you actually want? There is no answer..THIS..
If you are looking for 600hp you have shit tons of options. Turbos spooling fast and having capability of your goals as a max or a 6466 which you can use for well over 800hp but with sacrificies for down low performance.

Me personally. I would check Pulsar Turbos. They copy the known brands and make them even a little better. Great turbos. Take your time for choosing. If you are not sure. Contact the companies and they will help you decide! That is what customer service is for.

With Meth you are bringing a lot and really a lot of cooling which makes your stock block happy. 100% meth is nonsense anyways but each to their own. Research 100% distilled water injection and you will find out that even that is a viable solution where ppl wrote doctor thesis about.
Meth is not the answer to everything.

But for your posted turbos. 6266 and 6466 donĀ“t seem to be so different but the 6466 being better top end and handling the low end like a 6266.

Your request ist too general and you will not get any useful input if you will not specify your specific needs.

Its just like the question "what is the best oil" ....
 
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seb.apprenti

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I have to carry out a few more tests to be 100% sure that my problem really comes from my twins. Currently I have a big "surge" problem... I've been doing tests for weeks, changing parts to be sure that it's not a turbo problem... The next test will be reassembly of the original turbos to see what is happening. I put the YouTube link of what's happening at the end of this message.. I live on a small island lost in the Indian Ocean and I don't have access to E85... that's why my choice is directed towards meth. I don't know much about single turbo installations...I understand that my question seems "generic" but I am totally lost with all these possible arrangements
Link
 

seb.apprenti

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Regarding the problem on the video, I have carried out numerous tests. this noise was recorded with the map race... around 25psi. I received a more doice Map test (18psi)..the phenomenon is less strong but present. I even tried a stage 2 MHD map (v7)... there was still a problem. my setup. hp800 gen2 intercooler 7.5 PR relocated inlets 3" (76mm) boost circuit CP vrsf for 335d tank bov Nike performance masata intake manifold full vrsf street exhaust system.. everything was dismantled and checked. new throttle body intake manifold gasket replaced by bms model PVC control boost circuit test control of the selenoids (try with the first selenoid to control the two turbos.. then with the second.. then with new ones.) I took the compressions (they are a little weak... but no significant imbalances) I checked the adjustment of my wastegates to be sure that it was not too tight I tried without the meth I changed my bov I tried without the inlets. I rented a dyno to see with my own eyes what was happening...there is a surge coming from the rear turbo.. and nothing is visible on the logs...it drives him crazy Currently my car doesn't look like anything anymore because there are so many things taken apart to carry out the tests. The last solution for me is to put the original Turbos back and see what happens
 

wheela

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Jun 4, 2021
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It sounds like the rear turbo is running behind its surge line (pic from different turbo attached filor reference). I'm trying to think of how it could be flowing low enough at that boost level for that to happen. Is there any chance the inlet on the rear turbo is collapsing? Between having high pressure at the rear turbo's outlet (from the front turbo) and limited mass flow from a collapsed inlet, it seems like those conditions could put the rear turbo into the surge region of its compressor map. Same thing if the rear turbos outlet was blocked, but if that was the case I'm guessing you'd have found that tearing everything apart.
 

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seb.apprenti

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It sounds like the rear turbo is running behind its surge line (pic from different turbo attached filor reference). I'm trying to think of how it could be flowing low enough at that boost level for that to happen. Is there any chance the inlet on the rear turbo is collapsing? Between having high pressure at the rear turbo's outlet (from the front turbo) and limited mass flow from a collapsed inlet, it seems like those conditions could put the rear turbo into the surge region of its compressor map. Same thing if the rear turbos outlet was blocked, but if that was the case I'm guessing you'd have found that tearing everything apart.
unfortunately these are not the inlets. these are the PRs... they are reinforced. I tried without the inlets, just with a mesh turbo filter...the phenomenon is still present
 
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ShocknAwe

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Sharing my experience. Had an issue with what I thought initially was surging or flutter on my HP800g1/N53 build. Only happened on certain tunes from Hydra and several but not all from another tuner. It ended up seeming to be rapid BOV actuation secondary to minor throttle events. I've self tuned at this point. No issues if I leave headroom in the tune and don't overboost. It really likes to overboost. Very efficient setup.
 

seb.apprenti

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Sharing my experience. Had an issue with what I thought initially was surging or flutter on my HP800g1/N53 build. Only happened on certain tunes from Hydra and several but not all from another tuner. It ended up seeming to be rapid BOV actuation secondary to minor throttle events. I've self tuned at this point. No issues if I leave headroom in the tune and don't overboost. It really likes to overboost. Very efficient setup.
Thank you for your feedback. my mapper is JSRT...we tried several Maps...it still does it.... we tried a test map (18psi)..very progressive...the problem is less important but still present. I tried with v7 MHD... problem less present but I still feel a little surge. a French mapper who knows Hydra Turbos very well, sent me a test Map...the problem is present. the surge phenomenon in speeds 3 and 4 is not really disturbing...the problem is in speed 5 (last part of the video)..this noise is unbearable and really not pleasant. I'm going to reassemble my original Turbos and see what happens. then I'm going to try to examine my hp800 gen2....if it works well with my OEM Turbos, I'm going to save money to be able to upgrade to single. I contacted speedtech... but jeff is asking me 1800 dollars for transport. I'm also looking at the Docrace kits without turbo...I'm thinking of buying a Pulsar turbo in Europe. I really have to think carefully and do a lot of research.. at the moment I'm still lost. As I write this message, I will be moving towards a docrace top mount kit, turbo pulsar 6466 with t51 mod. docrace says that there is no need for selenoide mac. so at the moment I don't know how to get decent power without blowing up my engine. I don't understand how to control the power of the turbo. my fuel is not great (95 octone EUR) but with my methanol installation, I can produce a lot of power I think
 

seb.apprenti

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He told me he's sorry I'm having a problem.... I'm not going to insist...I'm tired.... I'm going to save money and move on to something else.
 

odesh

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Mar 6, 2023
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Thank you for your feedback. my mapper is JSRT...we tried several Maps...it still does it.... we tried a test map (18psi)..very progressive...the problem is less important but still present. I tried with v7 MHD... problem less present but I still feel a little surge. a French mapper who knows Hydra Turbos very well, sent me a test Map...the problem is present. the surge phenomenon in speeds 3 and 4 is not really disturbing...the problem is in speed 5 (last part of the video)..this noise is unbearable and really not pleasant. I'm going to reassemble my original Turbos and see what happens. then I'm going to try to examine my hp800 gen2....if it works well with my OEM Turbos, I'm going to save money to be able to upgrade to single. I contacted speedtech... but jeff is asking me 1800 dollars for transport. I'm also looking at the Docrace kits without turbo...I'm thinking of buying a Pulsar turbo in Europe. I really have to think carefully and do a lot of research.. at the moment I'm still lost. As I write this message, I will be moving towards a docrace top mount kit, turbo pulsar 6466 with t51 mod. docrace says that there is no need for selenoide mac. so at the moment I don't know how to get decent power without blowing up my engine. I don't understand how to control the power of the turbo. my fuel is not great (95 octone EUR) but with my methanol installation, I can produce a lot of power I think
Use some other carrier service. The direct shipping to Finland from Speedtech would have been like $1200. Ended up using Jetcarrier.com (they unfortunately don't ship everywhere), but there are similar services that will do the same thing on more countries. The final cost for the shipping trough them was only around $200, so there is a massive difference. I hope you will figure out the problem :/
 

ktb_e92

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Apr 16, 2024
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Hey Seb, I would say SpeedTech's bottom-mount kit with a Precision 6466 Gen2 turbo and TurboSmart wastegate would be the way to go. Many people I know regard the feel of a bottom-mount kit as very responsive when comparing them to twins. Considering you spray a good deal of meth, you should easily reach around 600whp with a 6466 on ~20psi with 95oct.
 

seb.apprenti

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I'm sorry, I forgot to update my situation. I put my OEM Turbos back in place to see if the problem disappeared. jsrt made me a new stage 2 map. unfortunately the problem is less serious but still present (surge phenomenon) so I decided to reassemble the OEM parts one by one until I found the problem. I started dismantling the intercooler and the Jpipe. and there...I saw something that didn't appeal to me anymore. The silicone hose that comes out of the intercooler towards the Jpipe ends up a little bent when it is installed. I think this causes a flow restriction, which causes back pressure...which causes a surge phenomenon. I installed my OEM intercooler and the OEM Jpipe, everything is fine for the moment. here's how I'm going to do it. I'm going to install the Hydra again. I ordered a 7.5 bms intercooler because it has a plate inside for better air diffusion. I also ordered a transmission oil cooler to remove the small OEM radiator (it is small but it takes up space next to it). of Jpipe). I'm changing my coolant radiator, I took the one designed for the manual gearbox, it will be cleaner and it avoids putting caps everywhere. I therefore also ordered the water pipe which goes on the engine block, I took the model for manual gearbox. This is where I am currently
 
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seb.apprenti

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Once the assembly is complete, I will come back to give you news. I ordered the transmission oil cooler on the BMS website but bad news, they are awaiting restocking..so I have to wait
 
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mwpa71

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Sep 26, 2022
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G'day mate. I'm not an N54 but I do have a 600whp ish n55 on wmi.
I spray around 2750cc (6 x225) plus 2 x 700 cp.
Was just thinking you might be a little short in that area.
You need a bigger pump at this level for pressure.
Good luck with it all šŸ‘
 

seb.apprenti

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with the hp650 I did 535 whp (95 ron+ 1500cc 100% meth) namely that I had a boost leak (I had a poorly adjusted and leaky wastegate) with the hp800 gen2 if I can get closer to 600 whp, I will be very happy. at 25 psi, the wastegates are barely at 50%. what will limit me is the fuel... but it is more than enough for me
 

surge89

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Feb 27, 2024
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Wow its crazy what an upgrade the n53 head would be then, going from 535 at 25psi to 600 at 18 without meth... I think I'm gonna start looking for the n53 head haha