200ci+turbo

[Anonymous]

66sprint6

the ist one- the 300zx is a good one to get provided its in good nick.

the second one is a bit to small on the exhaust side so no go there.

the third would be almost perfect but is ment for a 2 lt so the exhaust side will be a tad small and become a bit of a restriction when u go up to 16psi.

the last one is waaay to small the exhaust ar should at least be more then .60ar this last one has a .48 so its too small.

try and aim for a .80ar exhaust housing, i think from memory the 300zx has a .80ar on them.

personly i'd go a t04 in the end as you can thus has 28psi when you can afford

cheers.joe.

the compressor sides arnt as critical as the exhaust side cos the exhaust side determines the character of the engine (ie. boost response) you have to find a balance between fast boost response and least restriction.

the t3 frpom the vg30 (300zx) is perfect it will hit boost by 2800rpm regeion and hold out to a max of 18psi to the 200 cu in.

do not worry about the fact that it wont spool up till 2800 as remember ur only of boost once (1st gear) and for highway you dont exactly want to be sitting on full boost now do you?. also the turbo will generate more torque in the lower regeions of the rpm range then the standard car and thus u'll have better fuel economy.

cheers.joe.

 

[66Sprint6]

Hey GM, actually, I should call you destroyer lol, you have been a great help. T04, is that the same as the Gerret T4. I like the looks of the T3/T4 as well, is that a good one. Ive found a few 14b turbos off an eclipse, how bout them. Im gonna try the first one, the 300zx turbo for now (try to win it for cheap that is) then maybe one day Ill swap it out in favor for mooooooore boost, that is, when my motor can handle it. Thanx again!!!
Matt

 

[66Sprint6]

I have looked around for some .80 A/R turbo's, not too many around, Ive found a ton of .50's but no .80's. Any good place to find one other than ebay, lol.
Matt

 

[CobraSix]

Gm...I don't doubt your experience...what is the difference between forced air with a super and with a turbo? Just curious why you can run more boost with a turbo then with the super with the same static compression ratio?

Slade

 

[Anonymous]

I've been reading up on the topic and have found a couple of books that have some good info. Maximum Boost by Corky Bell has a lot of good info for the DIY turbo system. He tells you how to select a turbo based on the comporessor map and intended application, intercoolers, etc. There's a lot of apparent wisdom there, though I have yet to apply it. He's heavily biased toward EFI, so talks little about carbs.

I haven't started shopping around parts yet. Have to get the motor ready with everything else, first (OZ head, fuel & ignition system, freshen up bottom end). My intention is either a TBI or multi-port system running 6-8 lbs of boost. Moderate for daily driver reasons (it'll happen someday, really). It's probably a good ways off. I like to over-plan things though. So I'm starting now.

Here's one question that hasn't come up yet, and I'll post it in a new topic for discussion- cam selections for turbos.

--mikey

 

[CobraSix]

I wouldn't want to run a turbo without EFI, but that is me...

I'll check out that book...

Slade

 

[Anonymous]

Gm...I don't doubt your experience...what is the difference between forced air with a super and with a turbo? Just curious why you can run more boost with a turbo then with the super with the same static compression ratio?

It has to do with the compressor efficiency. When you compress air, it heats up. Hotter air means more likey to get detonation. Also means less dense intake charge (less power). Turbos heat up the intake charge less than superchargers due to their better compressor efficiency. Turbos are up in the 70+% peak effiency. Supercahrgers are around 50% or less. The air will heat up some given amount when compressed due to a bunch of thermodynamic effects. Then there's a little extra heat from compressor effieciency. Take the theoretical (ideal) increase, divide by the compressor efficiency (as a decimal- 70%=0.7) and you get the total temp increase. A 70% efficient compressor heats it up by a factor of 1.4 times over ideal. A 50% compressor heats it by a factor of 2.

Adding an intercooler makes it even better. Take the heat back out of the intake charge before it hits the engine.

At least that's what the voices tell me.

--mikey

 

[CobraSix]

yes, but turbos have the side effect of heating the charge due to proximity to exhaust gases. I know the turbo on my Volvo gets really hot (red hot at times) and for that reason most turbos have to have an intercooler.

Maybe I'm way off base though.

Slade

 

[Anonymous]

I'd assume that there would be some heat x-fer to the intake air from the turbo housing. Consider, though, that the air isn't in there very long to asborb any heat from the housing. It would certainly soak up some heat there, but I suspect that the heat from being compressed is the dominating factor by a wide margin.

The intercooler isn't specifically for the red-hot turbo housing- it only cools the intake air after it comes out of the compressor. Pretty much all turbos will get that hot, and not all turbo systems use intercoolers (though they probably should).

As a side note, they do make water-cooled turbo housings for bearing cooling.

--mikey

 

[Anonymous]

Cheep idea for a pop off valve we used on a Rambler waggon I6 was a radiator cap. Worked great for years but needs to be replaced periodicly. Heat causes it to loose pressure rating over time.

 

[Anonymous]

Look for a used Buick Grand National turbo if you can, those motors were 3.8L, close enough to our 200/250s. The compressor is .60 A/R and turbine is .64. I have several complete turbos and turbo parts stashed in my little space. I'll get it sorted out and have the Comet running soon enough.

The hardest part for me is getting a turbo header/manifold fabricated. There's not a lot of space on the passenger side of the Comet. I imagine this would probably be true of Mustangs and falcons too.


db

 

[addo]

You're right there, Dennis. Looks as though the best turbo location is forward of the shock tower and up, just like a crossflow. Too bad the manifold's there.

Pictures in my mind have a version of the crossflow EFI manifold running over the valve cover, with an intermediate manifold against the head, whether 2V or hacked log. Either way, six runners and bosses for injector mounting... The Argentinian heads are actually better for this type of idea because the intake holes into the head are not at such an angle as the 2V (you have to look closely to see what I mean).

Adam.

 

[Anonymous]

Gm...I don't doubt your experience...what is the difference between forced air with a super and with a turbo? Just curious why you can run more boost with a turbo then with the super with the same static compression ratio?

Slade

when i say supercharger i refer to the old roots/screw psi blowers (the big metal mountains)
the are constantly creating positve boost pressure and the blower housing endsup heating up a fair bit and its quite hard to puta intercooler device in there as well.

a turbo whilst heating the air still, it never see's the same inlet charge temps unless over stretched (hence me saying go grab a largish turbo)

the coolest running type tho has to be a vortech style supercharger (centrifugal) the are essentialy a belt driven turbo and thus do not have the associated heat of the exhaust housing like a turbo so inlet charges are cooler then a turbo.

but over here in aus. all the mega hp cars run turbo's (1514hp at the wheels from a stroked 304 holden engine(small block chev pretty much). thus it would seem the turbo is the way to go.

dbzOkole- that turbo you suggest would also be great for a cheap set up. although id dare say the max hp potential would be far less greater then the vg30 set up.

turbo 2256-for even cheaper pop off valve (blow off valve- bov) you can run a air injection valve that is found on some cars to better improve tailpipe emisions.. you remove the reed valve in them and hey presto you have a bov.. i have more in depth stuff here ...ask if you want it.

cheers.joe.

 

[66Sprint6]

ok,
when it comes to BOV's, I heard somethin about venting them into the atmosphere to get that awesome sound, or back to the intake??? Something like that. Whats the deal with that? Does it do you any good to vent it back to the motor or to the atmosphere. Anyone?
Matt

 

[Anonymous]

a bov venting to atmosphere will make the ppttsch sound the one venting to the inlet (plumb back) one dnt make the big ptsch full sick sound.

the plumb back one was mainly intended for efi cars that have maf (mass air flow) meters as when there was a opening (ie. the bov venting) in the inlet tract the maf would get confused and dump fuel into the car and all that fuel dosnt get burnt upm in the chambers you then got a big puff of black smoke a back fire and some black soot on the back of ur car.

i use a plumb back one as well but mine is map sensored so i dont have the dramas associated with the maf set up. but my only reason for running a plumb back was so you couldnt hear the ptsch sound cos the police are attracted to it and thus hassel me over my car.

the venting to atmosphere ones are just that and are made for noise

another reason for their manufacture is that when you are accelerating the turbo is making boost but once u back off and the throttle is closed the turbo is still making boost (due to the engine still revving down). so air is screaming thru to the throttle , hit the throttle and has nowhere else to go except back where it came from. the air re-enters the turbo and forces the compressor to slow down/and or stop. but once you start to accelarate again the turbo has to spin up again to generate boost.

venting the boost means you do not get boost hitting back on the compressor.

there is not any really hp diference between the 2 types although the plumb back has been found to improve boost response a bit more then the vent to atmosphere one as the boosted air get's rederected back into the inlet tract before the turbo and thus the air flows in the same general direction as the new/fresh air comming into the system, and since the air is still compressed ina way it hit thes compressor wheel harder and which make the turbo spin up better.

cheers.joe.


ps. jeez talk about post whoring lol!!

 

[66Sprint6]

Destroyer, whore on man, you are amazing, lol. You have inspired me and given me the will to keep persuin this dream! I have gotten so many answers from you, and then I have all the others out there helpin, so Im set!!!! Keep the info comin, and please, if you have any other info I should look into about this, please help. What about fuel dispersion on my carb?
Matt

 

[Anonymous]

Destroyer, whore on man, you are amazing, lol. You have inspired me and given me the will to keep persuin this dream! I have gotten so many answers from you, and then I have all the others out there helpin, so Im set!!!! Keep the info comin, and please, if you have any other info I should look into about this, please help. What about fuel dispersion on my carb?
Matt

no worries mate, only too glad to help.
if you ever got any questions just ask mate,

hotmail is idontlikeholdenandhsv@hotmail.com

but as for ur fuel dispersion... um.... i think i hear my mum calling me to dinner lol. i think someone else is better answering that one as i know bugger all about carbies! lol

i generaly play with late model efi falcon motors,

but i strongly suggest efi you'll be suprised how little it would cost for a efi set up to run it.

the cost of a carb and then a decent manifold would be about 3/4 of a efi set up.

a delco computer from just about any gm car from the 90's will go in use all the sensors from the donar car just nock up a wiring loom to suit and bob's ur uncle.

use some jap import fuel injectors as well and a bosch motorsport pump for fuel.

another way would be the megasquirt set up.

all it takes is some balls to try and a little bit of brains and some good people helping you. (it how i learnt!!!!!)

its pointless playing with carbies when theres good cheap efi options out there. as efi is some much more precise in its fueling and tuning is so far better.


cheers.joe.

 

[66Sprint6]

Well,
Im not sure about efi, I might have to look real deep into that, but for now I think Im gonna stick to my carb because money is REAL thin right now, lol. I was wondering tho, what are some other mods that might help get the motor ready for some boost. I was lookin at roller tip rockers, new pushrods and lifters. I was also lookin at a new cam, but seems for a turbo that might not be a good idea anymore. Is there anything else I can do to build up the motor, perhaps to the block that wont be too bad off expensive but really ought to be done? Thanx again for all your help guys, keep the info coming, it keeps me afloat!
Matt

 

[66Sprint6]

Oh yeah,
Im also lookin for a good intercooler. Anyone got any ideas. Ive found a couple Volvo and a SC tbid one as well. Any one have a preference when it comes to intercoolers. Im up for aftermarket too, just wanna know what everyone thinks.
Matt

 

[Anonymous]

66Sprint6- those volvo intercoolers will suffice and you may be able to squeeze it forward of the radiator. As you know, they usually sell for $50 on EBay. If I had my "druthers", I would get a volvo intercooler instead of my overpriced hunk of AL. I plan to mount my intercooler in front of the radiator too, but towards the bottom of the radiator, to somewhat concealed it.

Another thing to consider is the size of the intercooler. Go too big and more lag, go too small less lag but with still "uncooled" air.

This planning part is fun. It's taken forever to build mine up because I like to play with all the variables. But enjoy it, stay enthusiastic of the project and be sure to post pics, aight.

db