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Discussion Starter #1
what is the quickest spooling turbo you can get off something the size of say a T78?? have read previous debates about lag etc, but now quite a few people have used these turbo's for a while, what is the general consensus of opinion on them??
 

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Big turbo

hi tiggs

go for it big turbo T78 & 2.8 hks stroker kit etc will fly then
is a possiblity if u sell the sunny !!! then can really scare yourself

lee
 

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I think that someone answered about a big single or indeed big twins, If there is a lot of lag then you can always change down..

depends what you want the car for I suppose, if you want a drag strip monster or long circuit car then the single should be ok but if you are going for twisty b road hacking then the twins would probably be a better bet..

Any input from the big single guys ?

I am also interested in this for the next project..

what are the criteria for selecting the single conversion over the twin setup ?

/Steve
 

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Discussion Starter #5
this is why I wanted to keep the sunny, just for the B roads fun. I have watched with interest the debate on twin or single....I want to do drag events mainly as I have the sunny for track racing...I do want an external wastegate though if this makes any difference.
 

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this is why I wanted to keep the sunny, just for the B roads fun. I have watched with interest the debate on twin or single....I want to do drag events mainly as I have the sunny for track racing...I do want an external wastegate though if this makes any difference.
There are plenty of options for drag racing. T78s, T88s, T51R-SPLs are the ones to go for if you want to go down the single route, or you can do big twins like 3037Ss or the 3240s which are used by the fastest RH9 drag cars in Japan. All very expensive though :(
 

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Tiggs

I think it is all in the mapping as when I have been out with Glen and rupert they do not seem to have hardly any lag at all and I was very suprosed what the supertanker size ones they have.

I presume they all have the power FC so mark has been able to map them very well to ensure optimal performance and a very nice pull through the range.

The external wastgate sounds mad but no idea why they do this? Maybe the config of the single works more efficiently if it dumps air in this way...

Either way a T78 is sweet. Does anyone run a T88?
Is the T88 the same size as the HKS T51 that is one the white OPtion 33gtr??

NLW
 

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The T51 is bigger than the T88 and in a right configuration can flow enough air for 1000bhp.

I've also been out in Glens and Ronnies T78 equipped cars and was surprised at the fact that they are very drivable. Full boost probably comes at 4500 and up but there is enough below that to drive the car normally. A testament to Mraks work!:)
 

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IMHO tiggs, choosing the turbo (twin vs single) generally comes down to the power you want and the money you have to spend. The twin route is more expensive than the single by a factor of almost 50 % for the kit. However, for a given maximum hp (all other things equal), a twin setup should come on earlier (by about 500rpms) than an equivalent flowing single. Also, singles are great for mid range punch while twins deliver power more gradually through the upper rev range.

Having said that, the characteristics of the power delivery will be heavily influenced by the turbine A/R, cams and tuning. Between these 3 variables you can dramatically change the responsiveness of the engine. I'm going through this decision making process at the moment and looked through many RB26 engine configurations and dyno charts that support this.

nwelch, external wastegates are a must on big turbos as the larger turbos are designed for big boost pressure - internal gates can't control the boost build up sufficiently quickly. Spring pressures and wastegate hole size are the issue.

Cya O!
 

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Discussion Starter #10
Cheers,

Yeah, am definately going to go big single...well, until I change my mine again!!

what I want is low mid range, shove you in your seat punch....I know big singles give lag, but thats in hand so to speak! I am thinking along the lines of the T78, but would a T88 be better? again, it will be fitted with an external wastegate!
 

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T88

T88
 

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Discussion Starter #12
GTSM, why do you think a T88 would be better over a T78....do you think it will flow better and spool up quicker....what are the merits to it????
 

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t88

The bigger the better !!!

well no actually you might get more lag but has more potential for future,steel head gasket and loads of boost = 1000bhp
(oh and loads of money)

lee
 

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hi

you have pm
 

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Discussion Starter #15
the bigger the better.....well, not really....it depends what you want to use the car for...as I have said, I want to have mid range punch and I dont know if a T88 is the most suitable...
 

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turbo

u r very right depends on what u want it for mid range puch is good,why not tune it for drag racing !!!!


lee
 

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Discussion Starter #17
ok, so does anyone have an opinion on which is the better turbo for what I want to do??
 

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Opinion

I do:

For drag events all that counts is power, lag means nothing.

In which case go for the absolute biggest turbo you can find, with wildest cams and extra capacity if possible.

But make sure you have budgeted for the required:

Injectors
Fuel pump
Cams/Springs
Triple Clutch
Pistons
Rods
Oil Pump
Radiator
Intercooler
etc etc

You will need all of the above if you plan on going 650+bhp, which is what any of the following will deliver:

Singles:

T78
T88
T88H
T51R SPL
T51R KAI

Twins:

T618Z x2
T67 x 2
HKS 2835 x2
HKS 3037 x2
HKS 3040 x2
HKS 3240 x3

All above available in various a/r ratios.

Tell me what bhp you want and what capacity engine you plan on running and I'll tell you what I'd recomend eg at 650bhp a T78 is better than a T88, since it spools faster, whereas if you want 800bhp then you need a T88 etc etc.....

Guy
 

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Guy,

Do you know what the lilfe expectancy between rebuilds (mean time between faliure) is for a 2.8 kitted 800 bhp beastie ?
there has to be a compromise between reliability and power in my case..

I remember reading one of your posts which stated "above certain power the engine should be seen as a consumable".

The reason I ask on this thread is that I am sure Tigger needs to take into consideration how often the car will be in the garage.

I am also looking into this exact dilemma for a future project.

thanks for your input.
Steve
 

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Why just stick to the usual Trust/HKS turbos? There are plenty of places (especially in the States) who can put together just what you want.

Phil
 
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