twin blowthrough turbo using su's

[pauly_adams]

hey everyone was wondering your views on a blowthrough turbo setup using twin su carbs. the carbs ill be using will be British ones with ballbaring shafts and ballbaring dashpots mind you there air tight, the turbo will be a garret t28 highflowed from my brothers 250rwkw 300zxtt this will also include his blowoff valve and my 2.5inch exhaust. my thoughts are that i will try and run about 5 to 6 psi to see how it goes, i have a rough drawing of what ill do and was wondering if any one else has done it and could give me some pointers.

 

cheers pauly

[NZeder]

I have not done it but I only went to look at a 240z with just such a setup once (shame the body was so stuffed) in period Janspeed was one of the places selling a kit for this setup too.

[XRQTR]

A T28 running 5-6 psi should be fairly docile, it will give you some good axtra overtaking power but not too much more, they're good for up to 2 litre cars, you shouldn't have too much drama as the volume won't be as high as a T3 or bigger. At the very least it will be a good learning experience as you can start it off on usable low boost and then wind it up to see where the carbs/gaskets let go.

 

Also I hope you'll be running an electronic dizzy as well as getting the carbs re-jetted for the extra air up high in the revs, it shouldn't need much but to be on the safe side you'd want to be testing it all on a dyno before you go out on the road and melt a piston or 6. 

 

The guy that was selling the supercharged Z on ebay recently was running a toyota side mount supercharger through twin carbs.

[pauly_adams]

yeh i did see that supercharged 240z on ebay, as for the needles and dizzy i dont have them yet but did think about it and am going to do it. by the way i have 2x highflowed t28's at my desposal and there good for 25 psi but theres no way it will be running that much as i like my life and my car .

 

 

cheers pauly

[RBZ 260]

twins sounds a bit too much. it will be laggy thats if it will hold up till 6psi boost rise.

im assuming this is going on the L26 l28.

 

single turbo will simplify things and u wont get any gain from putting 2 on. if u had two smaller t25 than u get the benefit of quicker spooling and better top end than a single t28.

 

usualy the twin turbo setup uses smaller turbos. just lookat the cars that have them from factory.

designed to give quick spooling (less lag) and still enough for top end. best of both worlds.

 

mazda has done a sequential  setup on the 13b and 20b. a smaller one pumping the bigger one. work ok in stock form but try raise the boost as both need to be matched. hence they rip them off and install a single bigger one.

 

also if its stock engine im sure u wont have any issues destroyin it with a single turbo setup.

 

to make it last prob a decomp gasket, and in my preffereance efi.

 

EFI makes tuning simpler and in long run cheaper.

 

a simpler solution just dropin in a rb turbo engine 

[FuzzyDropbear]

My 260 was running a single T28 with a single stromberg carb. I have never had it running (was a restorers delight from the back shed sort of thing) but it was running well, before it sat in the open for 6 years without moving...  :'( Then I got it 

 

However, from what I have read, the single turbo and carbi seems to have been the most popular way to boost the L-series engines.

 

I was considering a similar setup to what you described, but I figured that there was a reason people (including a few tuning houses in Britain) have only gone for the single turbo route.

[pauly_adams]

my engine is a rebuilt l26 with a rebuilt e88 head with a bit of work done to it, as for the efi this setup was just for a shits and giggle experiment and if it goes well it will stay on. the only thing that bothers me is that i will blow a head gasket and i dont like changing them, all parts will be custom made by me and a mate at work whos a welder/ fabricator. i hope it all goes well it should go ok not too sure if i should run an intercooler or not but only running low boost i dont think it will be needed any infor on this would be apresiated.

 

 

thanks for the input and keep it coming.

 

cheers pauly

[RBZ 260]

Pauly u got the best connections. just drob an RB for kicks lol. wont blow head gaskets. it may blow ur drive shafts and maybe diff 

 

to ur setup.

 

ive seen a T4 turbo on L24 with single stromberg carby. though this was a suck through system. so no intercooler or blow off valve can be used.it did have a decomp gasket and was very realiable. laggy and had bit off power.

 

i wouldnt go twins. Single turbo. u would have to do something about carbies as they will lean out and or pop under positive pressure. u did mention sorting that with some sealed bearings etc...

 

what i was thinking to do on my 240z (once i get to it) since i got the matching number engine.

is to rebuild it have a decomp gasket to drop the compresion ratio.

install a L28 efi system or even use a Rb20/25 efi electronics, adapted to L24

A T28 turbo intercooler and new exhaust. make it look retro and hide the ecu somewhere inside the engine bay. (no holes to cut in the firewall, so the car can be returned to stock)

 

 

i will try and check the cost of these things and than compare to alternatives,

if end ups to costly ill just drop an RB or SR in it at least wont have any issues in tunning it but still install it in a way that can be returned to stock quite easily.

 

if u have the bits than just go for it but not the twins. even with single i think your gasket will let go.

 

 

 

 

 

[pauly_adams]

i was thinking of going a sr20dett as my brother knows some who is selling a whole engine, loom etc for 1k which is a good price. the reason why i was thinking of turboing my l26 is due to the original engine being in it and was just after something a bit different. as for the carbs yes thay do have sealed bareing for both dashpot and butterflies. ive been doing my research and it said its ideal for blowthrough turbo. i was going to do drawthough but as you said i cant run a bov or a intercooler.

 

 

cheers pauly

 

[RBZ 260]

SR20DET for 1K what u waiting for 

 

unless its got a hole on the side of the block. 

 

that is cheap.

 

hey no sr20det powered 2+2 yet. thats different

 

 

[pauly_adams]

yeh the unfortunate thing is that my work has more or less shafted me so now im just getting one shift a week. so if i get this new job in the nt ill be doing a sr20 conversion.

 

 

cheers pauly

[XRQTR]

Dude, buy the SR20, put it aside and even if you don't get the job you have a cheap motor just save the rest over time

 

Do it, Do it

[pauly_adams]

i am realy considering it i find out this week about the job. and if i get it ill buy it, if not ill buy it pending me getting a new job lol this turbo setup is just for the shits and giggle factor

 

 

cheers pauly