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Single Turbo or Twin Turbo?


Firestorm

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Are there any benefits to fitting aftermarket twins at all?

 

Sorry I meant in comparison to a responsive Single....

 

If it was the choice between having a SP71....or T88 making 800bhp and the twin GT2835's I know I'd want the twins,

 

But question for ya...is there only 3runners travelling to each turbo on your Blitz manifold? If so arent you down on pressure in comparison to the 6 to 1 manifold on a Single, therefore your spool is offset

 

The only benefit I can see is that On a big compressor wheel like a SP71 e.t.c it would be harder to get that thing running, than 3runners would take to get the ones on the twins moving but I'd like to see a dynograph to compare the actuall differences on say two different 800bhp setups, do the twins justify the added cost/weight/complication/maintenance esp as your seeing the almost same result from both i.e both on boost at the same time?

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eh? Are you basically saying that you think there are no upsides to fitting aftermarket twins over the stock tubbies? Somehow I doubt I would have made 560bhp on my stock tubbies!

The turbo's I've got are individually rated to 450bhp, so with a built engine, even accounting for losses due to linking them together it's going to make over 750bhp.

The benefit of the twins compared to a single will be the spool. Right now I'm down on an equivalently powered single because I'm not utilising their full capability, but when they get up to higher boost levels that's where the twins should come into their own. :)

 

Just out of interest at what boost did you make 560bhp Tony?:)

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I do like Lee P's efforts.

 

very nice car, any dynoplots out of curiosity, I so wanted the HKS twins a while back then got put off when I experienced them

 

Firstly because I felt sick at all that power in a passenger seat, secondly I twiddled my thumbs until they came online, but f*ck me when they did!!

 

Verdict 800odd bhp is too much for our roads imo,

A small single suits my driving

 

I'll say the reason why, you know how when your driving along say a country road and *ahem are feeling that you would like to overtake like...NOW, you dont really have a choice with a laggy turbo setup, you need a much longer space/gap to get up the rev range, its only really usefull on the motorway, and even then you need to make sure its clear for the next half mile of so before you downshift, its fun but just gets annoying that your restricted - even though you have all that power

 

its also really annoying when those little f*ckers in the Evos are about half a mile in front before you start to catch up when theyre running half the power!!(Thats a problem with all rwd cars though I suspect)

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very nice car, any dynoplots out of curiosity, I so wanted the HKS twins a while back then got put off when I experienced them

 

Firstly because I felt sick at all that power in a passenger seat, secondly I twiddled my thumbs until they came online, but f*ck me when they did!!

 

Verdict 800odd bhp is too much for our roads imo,

A small single suits my driving

 

I'll say the reason why, you know how when your driving along say a country road and *ahem are feeling that you would like to overtake like...NOW, you dont really have a choice with a laggy turbo setup, you need a much longer space/gap to get up the rev range, its only really usefull on the motorway, and even then you need to make sure its clear for the next half mile of so before you downshift, its fun but just gets annoying that your restricted - even though you have all that power

 

Gotta agree. I wasn't aware before that the sequential system was ditched. :(

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i need an AFR gauge methinks- defi tho

 

I dont think Defi do an afr gauge as of yet...well not in BF edition anyway

 

The Innovate would go along nicely with those

 

Stage 1 systems are varied with manufacturers, with your setup in your sig, budget around 5g if you want the minimum that is required for a Single setup,assuming your good with a spanner and your cooling/clutch setup is sufficient.... then you have brakes e.t.c (if you have UK specs they are fine) It really isnt as cheap as the people behind the kits would have you believe

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Sorry I meant in comparison to a responsive Single....

 

If it was the choice between having a SP71....or T88 making 800bhp and the twin GT2835's I know I'd want the twins,

 

But question for ya...is there only 3runners travelling to each turbo on your Blitz manifold? If so arent you down on pressure in comparison to the 6 to 1 manifold on a Single, therefore your spool is offset

 

The only benefit I can see is that On a big compressor wheel like a SP71 e.t.c it would be harder to get that thing running, than 3runners would take to get the ones on the twins moving but I'd like to see a dynograph to compare the actuall differences on say two different 800bhp setups, do the twins justify the added cost/weight/complication/maintenance esp as your seeing the almost same result from both i.e both on boost at the same time?

 

You're right in that if you're only boosting to 1.4 bar as I am, then they're laggier. It's when you go to higher boost levels that they start to give bette results. IF I ran them up to 30psi for example, to get a turbo large enough to run up to that with decent efficiency it would have to be a big 'un. That's where having two smaller ones, although agreed running on only 3 runners, I think would give a slight edge.

 

Do they justify the added cost? No. Complication? No. Maintenance, No? Weight Yes. (They really don't weight that much. I would guess about 7 or 8kg. Defintely not more than 10)

 

Did you make 560bhp on sequential hybrids? Where they reliable...what make?

 

No lol. That would be impressive! I made 560 at 1.4 bar on the twins.

 

Just out of interest at what boost did you make 560bhp Tony?:)

 

;)

 

 

It's possible for me to get slightly smaller turbo's that would fit directly onto the kit I've got. They're rated to 330bhp each. I imagine if I fitted these then the spool would be a lot, lot better, and probably comparable to a small - medium single, but as I've just spent £1200 on smaller housings as it is, I don't fancy spending out another £1800 for a pair of yet smaller turbo's. I'm going to see if I can make the most of what I've got....

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Guest racing fan

Single turbos have proven to be the more efficient, less costly, and overall most optimal setups on Supras. With a set of aftermarket twins(setup in parralell like all of the current kits) you will achieve the exact same performance(lag/power) compared to a single turbo setup.

 

-zohair jaffery

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do most ppl upgrade from the BPU and the move on to stage 1 kit.?

 

as for the bpu- what are the best decat pipes and sparks that ppl use- as in irridium ones HKS etc.

 

i need an AFR gauge methinks- defi tho

 

firstly search for BPU ;)

 

de-cat is a decat imo, chris wilson, envy, paul whiffin...take your pick, ngk plugs are fine again search up plugs and you will find the info you need

 

secondly....no most people dont go down the single route after BPU mainly due to cost and those that do it on the cheap wish they had not cut corners, it is the next step as most dont opt for hybrids, but it costs a lot more compared to BPU

 

>>

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ah awesome okay chaps. im just trying to gather as much info as i can for bpu ing the car. i worked out i that basically have everything bar double decat, uprated fuel pump, sparks and a AFR gauge- so really i just wanted to get the best. obvisouly now it looks like its best to get NGK sparks and Walbro fuel pump.

 

but serioulsy any info (apart frm the advice given in the tech guide) as in peoples own experience when they BPU their car would be appreciated.. and how people went about it. etc:search:

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and how people went about it. etc

 

I'm not sure what you mean, its just bolt on parts, bpu is not an insane upgrade...in fact it is similar to upgrades you would do on any forced induction car.

 

If you want an optimum bpu setup,

550cc injectors(UK's)

Piggyback Ecu....remappable..ie GReddy Emanage

3inch Exhaust...your will need restrictor ring for 1.2bar

FMIC/Upgraded SMIC

New Panel Filter or Induction Kit...with heat sheild

Denso IK22's or equivalent NGK's

Walbro Fuel Pump...think its a 255pl/h

256 Cams if your car is J-spec...really not necessary

Make sure your car is capable of running 1.2bar because you have have de-restricted your exhaust side, turbo oil seals are more prone to failure bacause the pressure is only pushing one way.

 

If you source a set of good condition UK turbos I believe you dont need a restrictor ring, you may lose slight response but they are slightly more torquey and you can run them around 1.3-1.4bar without restrictor ring.

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If you source a set of good condition UK turbos I believe you dont need a restrictor ring, you may lose slight response but they are slightly more torquey and you can run them around 1.3-1.4bar without restrictor ring.

 

Not as simple as just swapping the turbos, the fuel and ignition maps are different, the downpipe is different and the manifold is different.

 

I also wouldnt run anything over 1.2bar on the stock map sensor since it only reads to approx 1.2bar, beyond this and fueling is in the hands of the gods.

 

Some say you can run upto 1.4bar on a UK motor but that uses MAF for fueling not MAP, i certainly wouldnt run 1.4bar.

 

 

Swapping to UK turbos IMO is not worth it.

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Not as simple as just swapping the turbos, the fuel and ignition maps are different, the downpipe is different and the manifold is different.

 

I also wouldnt run anything over 1.2bar on the stock map sensor since it only reads to approx 1.2bar, beyond this and fueling is in the hands of the gods.

 

Some say you can run upto 1.4bar on a UK motor but that uses MAF for fueling not MAP, i certainly wouldnt run 1.4bar.

 

 

Swapping to UK turbos IMO is not worth it.

 

I never knew the mani and downpipe was different...does all aftermarket dp's fit the UK and J-Spec cars?

 

Yeah I dont think their worth it either but they are stronger apparently, what I dont understand is the max I've heard on a BPU car is like 430give or take,the J-Specs seem to reach that too, so were does this extra 0.2bar of power go?

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I have hybrids already installed on my car when I bought it.

 

They have uprated steel internals and allows the car to run about 450 BHP. I love the sequential effect that is mantained with this setup. I do not like the idea of turbo lag, or a sudden extreme boost of power that you may get with a single.

 

I'm not sure what the exact definition of hybrid turbo is though, and whether it also encompasses bigger twin setups.

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I do not like the idea of turbo lag, or a sudden extreme boost of power that you may get with a single.

 

With the right turbo choice, a single can be just about as responsive as the stock sequential setup, eg. I get positive boost on mine at around 2000rpm. Infact I'd hazard a guess that my GT35R is similar if not more responsive than a pair of hybrid turbos.

 

Also the power is a lot more linear and controllable with a single turbo compared to the stock sequential setup. I'm sure more than a few accidents have been caused by the second turbo on the sequential setup kicking in unexpectedly.

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With the right turbo choice, a single can be just about as responsive as the stock sequential setup, eg. I get positive boost on mine at around 2000rpm. Infact I'd hazard a guess that my GT35R is similar if not more responsive than a pair of hybrid turbos.

 

Also the power is a lot more linear and controllable with a single turbo compared to the stock sequential setup. I'm sure more than a few accidents have been caused by the second turbo on the sequential setup kicking in unexpectedly.

 

so would get like a longer boost and quiker spool up with a single- i like the seqential as u get an extra boost of power just at the top end when u might need it. having never driven a uprated 500bhp single turbo- can i safely assume that u would get a big boost and just accelerate a whole hell of lot more then uprated sequentials. most people seem to say that it ends up being two turbos acting the same as single. although some have also said that u can keep that sequential mode.

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With the right turbo choice, a single can be just about as responsive as the stock sequential setup, eg. I get positive boost on mine at around 2000rpm. Infact I'd hazard a guess that my GT35R is similar if not more responsive than a pair of hybrid turbos.

 

Also the power is a lot more linear and controllable with a single turbo compared to the stock sequential setup. I'm sure more than a few accidents have been caused by the second turbo on the sequential setup kicking in unexpectedly.

 

Here you go Nic if you want to overlay my graphs over yours (the lbs & bhp are on different scales) :)

image

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