[FJ60_cruiser]

Great thread! I don't know that much about turbo's and I don't understand that well this mechanical info since i'm from Venezuela so I have a few questions: I have the stock carb, intake and exhaust manifolds, and i can get a t3/t4 turbo... so what else do i need for this setup keeping the stock carb? how hard and complicate will this setup be? thank's and sorry about my bad writting

[CruisinFJ60]

Originally Posted by Landcruisin'60

I'm not sure why you think you dont need a wastegate. The waste gates purpose is to regulate the amount of boost the turbo can build. If your target boost is say 16psi the waste gate will open so that the turbo only spins enough to generate that 16psi. If you didnt have a waste gate the exhaust gas passing through the turbo would keep spinning it and you have the possibility of generating way too much boost.

You are correct, most new cars have what are called by pass valves, or recirculating blow off valves. Basically a non-recirculating BOV just dumps the excess boost to the atmosphere, which in most cases causes the car to run rich for a second as its idling down because you just lost that air that the MAF already metered. If you recirculate that air back infront of the turbo inlet it can now circulate through the turbo again so you dont get compressor surge, this also makes it so your draw through MAF doesnt cause the engine to run rich because its still using all the metered air, instead of losing it to atmosphere with a BOV.

I think we all know why you dont get compressor surge with the diesel...it lacks something that gas engines have which causes the surge...

That being said I'm still a noob when it comes to turbos so not all of that may be correct.

ok for starters you may wanna re read my post, not once did i mention anything what so ever about a waste gate.
a waste gate and a blow off valve are 2 completely different things with 2 completely different functions.
and no again most new vehicles do Not have a factory blow of valve or "pass valve" or "recirculating blow off valves". in fact the only one i can think if is the 2G eclipse as seen here


and who says a diesel doesnt get compressor surge? better yet what are you calling compressor surge? since it kinda seems like you may be mixing information from multiple areas, and what is it that the diesel lacks that would make a difference in what we are talking about?...

im really not trying to be rude man but you have some mixed information for sure.

[Kurtis]

Originally Posted by CruisinFJ60

even on a blow through EFI design a waste gate is not required.
Good example...
how many factory turbo vehicle do you know that have an actual blow off valve... I personally cant think of any including the new EVO10. Unless you are running high boost you dont really have to Have a BOV, it may help the turbo last a little bit longer but i would doubt anything noticeable in a 0-15 psi boost range.

On my dodge i run 45psi and no BOV and still have yet to hear the turbo bark when you let all the way out of it at full boost. now some of you are going to say "well its a diesel its totally different"... well your right in the sence it can handle much more boost, but in the sense of a BOV all the same rules still apply. BOV if for turbo life no engine life, it will not make your vehicle faster, it will not mae it run better, it wont produce more horsepower ect.

Originally Posted by CruisinFJ60

ok for starters you may wanna re read my post, not once did i mention anything what so ever about a waste gate. .

I'm completely out on this and have no interest either way but the first line you mention waste gate
the diesils I have been around, powerstroke duramax have wastegates. All the gasser factory turbos porsche, saab all have wastegates.

[Landcruisin'60]

Originally Posted by CruisinFJ60

ok for starters you may wanna re read my post, not once did i mention anything what so ever about a waste gate.
a waste gate and a blow off valve are 2 completely different things with 2 completely different functions.
and no again most new vehicles do Not have a factory blow of valve or "pass valve" or "recirculating blow off valves". in fact the only one i can think if is the 2G eclipse as seen here


and who says a diesel doesnt get compressor surge? better yet what are you calling compressor surge? since it kinda seems like you may be mixing information from multiple areas, and what is it that the diesel lacks that would make a difference in what we are talking about?...

im really not trying to be rude man but you have some mixed information for sure.

Really? I coulda sworn my WRX came stock with a BPV, huh must be more of that mixed info. Also pretty sure my Saab I had was equipped with a BPV, and my friends V70 T5 Volvo. Actually I'm fairly certain that the vast majority of turbo set ups have some sort of BPV or BOV, or atleast every single one I've come in contact with. I could be wrong about diesel compressor surge...since I havent owned one. But I know the most common form of compressor surge happens when the BOV cant or doesnt release all the pressure between the turbo outlet and the throttle body. My friend with a 600awhp 2G Talon was expiriencing this at one point, now has a 44mm BOV. Like Kurtis already said you spoke about waste gates in the first part of your post..so I dont have to cover that.

I'm not trying to be rude, but you have some mixed info....

[CruisinFJ60]

Originally Posted by Kurtis

I'm completely out on this and have no interest either way but the first line you mention waste gate
the diesils I have been around, powerstroke duramax have wastegates. All the gasser factory turbos porsche, saab all have wastegates.

i re read my post twice before i said for him to re rear it... dunno how i missed that but i did, thinking one apparently typing another.
My Mistake.
and yes i have yet to come across a factory system that does not utilize a waste gate as you have mentioned.
but since on the subject, i do know many after market Diesel systems dont use a waste gate but again different animal than a gasser and was never brought up. just throwin it out there that some vehicles dont require a waste gate.

Originally Posted by Landcruisin'60

Really? I coulda sworn my WRX came stock with a BPV, huh must be more of that mixed info. Also pretty sure my Saab I had was equipped with a BPV, and my friends V70 T5 Volvo. Actually I'm fairly certain that the vast majority of turbo set ups have some sort of BPV or BOV, or atleast every single one I've come in contact with. I could be wrong about diesel compressor surge...since I havent owned one. But I know the most common form of compressor surge happens when the BOV cant or doesnt release all the pressure between the turbo outlet and the throttle body. My friend with a 600awhp 2G Talon was expiriencing this at one point, now has a 44mm BOV. Like Kurtis already said you spoke about waste gates in the first part of your post..so I dont have to cover that.

I'm not trying to be rude, but you have some mixed info....

looks as if i do have some mixed info myself as well. after a couple of google searches i did find than many seem to have a BPV. Some seemed to be pretty tough to locate but still there.

but where i was originally going with this in my first post was the fact that a BOV is not needed even on an EFI vehicle when running low boost. Ive been in many and driven many gas power vehicles with turbos and no BOV or the BOV not connected with no adverse effects.

[Kurtis]

Yea I don't see the need for a bov myself other than it sounds cool when you it pops. A wastegate seems like a good Idea though. Speaking of turbos I need to convince my wife she needs a wrx. My uncle builds race engines so most of the things I have been around are naturally asperated Chevy's. I wish I was knowledgable enough to build something for my tbi 350 in the cruiser. My problem is if I build it for 300-320 hp 400lbs tq then its getting to the upper limits of what a tbi is good for anyway. The tuning would kill me even If I could get it to put out enough fuel. Turbos seem to be a good Idea in general to me as you can set them pretty easily and you don't have to have massive amounts of boost at cruising speeds. I actually like the feeling of turbo lag myself. I remeber driving a turbo Carrea and loving the feeling of a turbo when you get on it.

[Slowerthanu]

Well, I can't see how a diesel would get compressor surge seeing as they don't have throttle plates but that is just me. When you lift on a diesel it reduces fuel, there is no change in the air flow path besides a reduction in rpms.

My 2007 GTI had a bypass valve on the turbo that vented to the atmosphere, factory.

The later Isuzu 4BD1T diesels do not utilize a wastgate, they are limited by load, fueling and rpms.

[CruisinFJ60]

if you go from boost to no throttle on a diesel it can "bark" the turbo which could potentially break the turbo shaft.

and the excess air cannot go into the engine if the rpms suddenly drop, and with the high compression they will slow movement much faster than a gasser. least thats teh only way it could seem to do it to me... if valves are closed air cant go anywhere.
but it does take a bit more than 25lbs to get it to surge. at 45 psi i havent noticed mine do it but i do know guys running the same boost on bigger turbos who can make em bark on command. likely due to more air being moved.

[ntsqd]

A BOV is a huge advantage to driving a manual trans, even with a low boost system. What I run into any time that I've got my 1.6L td or my 2.4L gasser spun tight and need to upshift is that it takes forever for the boost to come back. The 1.6L is the worst for this. A BOV would effectively allow the turbo to freewheel during the shift. I have a Saab BOV that I'm looking to make adjustable and integrate into the 1.6's air ducting. Not needed, but other than the stupid sound that it makes IMHO it is very desirable.

My current work is testing a very specific turbo. We have the ability to spin it to maximum shaft speed with hot gasses, but no engine. It takes a freewheeling turbo a surprisingly long time to "unspool" if there is no resistance to airflow. BTW, We can induce Surge in the turbo without any engine in the system at all.

[Tapage]

I'm running a BOV in my 2H-T setup .. and I'm surprised no ones here mention the turbo spike issue, that's the main reason to me run a BOV in my setup ..

[Landcruisin'60]

Originally Posted by Tapage

I'm running a BOV in my 2H-T setup .. and I'm surprised no ones here mention the turbo spike issue, that's the main reason to me run a BOV in my setup ..

Boost spike? When it boosts higher for a second and then drops to the set boost level?

[Tapage]

Originally Posted by Landcruisin'60

Boost spike? When it boosts higher for a second and then drops to the set boost level?

yap .. in my case each time that I close the throtle butterfly ( between shifts ) I get 3 - 4 PSI of turbo spike .. ( it was before my BOV )

[CruisinFJ60]

Originally Posted by Tapage

yap .. in my case each time that I close the throtle butterfly ( between shifts ) I get 3 - 4 PSI of turbo spike .. ( it was before my BOV )

Ive never had an issue with that...
Ive had boost creep... when your on it and waste gate is fully open and boost psi still continues to climb, or continues to climb then slowly bleeds back off.

[Mace]

Originally Posted by Tapage

yap .. in my case each time that I close the throtle butterfly ( between shifts ) I get 3 - 4 PSI of turbo spike .. ( it was before my BOV )

butterfly plates? on your diesel?

[ntsqd]

Originally Posted by CruisinFJ60

Ive never had an issue with that...
Ive had boost creep... when your on it and waste gate is fully open and boost psi still continues to climb, or continues to climb then slowly bleeds back off.

I also see a spike when shifting both engines, but it is most noticeable in the 2.4L gasser. It is due to the inertia of the air column suddenly having no place to go when the throttle plate closes. At really high boost levels w/o a BOV this has been known to bend the throttle plate(s). I'm not sure why I saw it at all on the 1.6L diesel, but it did happen though it was nowhere near as dramatic.

[CruisinFJ60]

Originally Posted by ntsqd

I also see a spike when shifting both engines, but it is most noticeable in the 2.4L gasser. It is due to the inertia of the air column suddenly having no place to go when the throttle plate closes. At really high boost levels w/o a BOV this has been known to bend the throttle plate(s). I'm not sure why I saw it at all on the 1.6L diesel, but it did happen though it was nowhere near as dramatic.

I was just thinking this as i re read his post.

I cant really test it in the dodge right now cause the gauge is pegged out at full boost. but it makes sense, tho i dont remember seeing it when i was only running 27psi either.

[lehiguy]

Originally Posted by Kurtis

Yea I don't see the need for a bov myself other than it sounds cool when you it pops. A wastegate seems like a good Idea though. Speaking of turbos I need to convince my wife she needs a wrx. My uncle builds race engines so most of the things I have been around are naturally asperated Chevy's. I wish I was knowledgable enough to build something for my tbi 350 in the cruiser. My problem is if I build it for 300-320 hp 400lbs tq then its getting to the upper limits of what a tbi is good for anyway. The tuning would kill me even If I could get it to put out enough fuel. Turbos seem to be a good Idea in general to me as you can set them pretty easily and you don't have to have massive amounts of boost at cruising speeds. I actually like the feeling of turbo lag myself. I remeber driving a turbo Carrea and loving the feeling of a turbo when you get on it.

I built the TBI 350 you're talking about. It wasn't hard or very expensive, the motor was already very strong with a carb, I just added the FI later. Modified TBI setups can easily reach 400HP in a 350, that seems to be about the practical limit for this rather basic technology.