Turbo manifold question

[ICEMAN707]

Why can't we do a downpipe turbo instead like this?
http://ludespeedperformance.tripod.c...ics/assem1.jpg


This was for a Ford Probe GT (2.5L V6) and it ran 14's on the 1/4 mile at 5 psi on a stock exhaust manifold with this downpipe turbo piping. I saw this at Ludespeedperformance.com.

If this is so, why is everyone having a headache about making turbo manifolds for our cars? I don't know much about turbos so bare with me. But, wouldn't this kind of setup with the stock A20A3 cast iron manifold with the turbo located at the battery location be a space convenient idea? I've seen drag cars use downpipe turbos as secondary turbos to eliminate top mid range lag and the manifold turbos as primary turbos for a dual turbo setup. So for all you turbo gurus out there, help me out.

[Doward]

I think it's simply due to the fact that it'd have to be custom, and small.

[Hash_man_Se_i]

Link doesnt work... so I can't really picture what you're talking about... but the sheer restriction that a normal manifold would create feeding a turbo would be rediculous.. you would be much better off just getting a manifold built... I'm sure its not that hard.

[Elijah]

It can be done.But there is so much custom work anyway.Why not just make a mani while ur at it.

[Robs89LXi]

Ahhh, a thinking man! You are right, I think this will be a very good setup, and that is what I'm already planning to do with mine. There are pros and cons though. I live in Texas, so heat is a big concern to me, and thus, I have to keep my A/C and radiator cooling fan. Moving the turbo over to where the battery currently is would solve this problem. Make access to the turbo much easier, and would possibly simplify charge/downpipe routing. Some cons though is that the longer the distance from the head to the turbo, is the cooler the exhaust gas becomes, and loses velocity, thus affecting tubine speed of the compressor. Another thing, is that the extra piping will create a lot of engine compartment heat. I think this can be managed with proper cooling ducts though, so it is not as big a concern to me. Like others have already said though, you would want a different manifold anyway, 'cause our stock one would be too restrictive. The ability to make a nice long runner, equal length, 4-2-1 manifold is appealing though, as this would help with the off turbo torque loss. Either way, I don't have much choice like I said, so it will probably be the route I chose. Keep us posted if you do it.

Why can't we do a downpipe turbo instead like this?
http://ludespeedperformance.tripod.c...ics/assem1.jpg

This was for a Ford Probe GT (2.5L V6) and it ran 14's on the 1/4 mile at 5 psi on a stock exhaust manifold with this downpipe turbo piping. I saw this at Ludespeedperformance.com.

If this is so, why is everyone having a headache about making turbo manifolds for our cars? I don't know much about turbos so bare with me. But, wouldn't this kind of setup with the stock A20A3 cast iron manifold with the turbo located at the battery location be a space convenient idea? I've seen drag cars use downpipe turbos as secondary turbos and the manifold turbos as primary turbos before for a dual turbo setup. So for all you turbo gurus out there, help me out.

[ICEMAN707]

the link works, you just have to keep reclicking on it till it works cus Tripod sux. anyways.... with this type of downpipe turbo setup, you can use a DC sports header with it and not have to mess with your EGR pipe. am i correct? also, you can have the turbo located anywhere you want depending on how you route the piping....like under the intake manifold for example...lots of room under there and the turbo is easily accessible underneath the car. as far as exhaust velocity, im sure not much is lost and using a t3/t4 hybrid turbo (that would normally be difficult to fit in front of the head) would solve that compression problem cus of the smaller diameter exhaust fan and larger diameter boost fan. further work on the intake manifold and head like b-series manifold swaps or port and polish would help alot too to increase air flow. again, im speaking from inexperience here, so bare with me. it's just an idea i had. i would love some opinions and input. i tried emailing Tom at Ludespeed since but never got a response yet.

[88accordhb]

interesting. i'm intriqued but the link is not functioning.

[ICEMAN707]

interesting. i'm intriqued but the link is not functioning.

click here: http://ludespeedperformance.tripod.com/ and go to "products" then probe gt and check out the turbo setup they have for that car. it's a downpipe-type turbo.

[A20A1]

not so much the length of the primaries but the fact that the larger tube diameter of the downpipe will cause a drop in velocity... thats why primaries that end closer to the turbo keep there velocity longer and will probably create ( more power / less lag ) that sort of thing.

The Probe is 6 cylinders so it has more exhaust to draw from and will probably be less noticable than a 4cyl.

Other then that wrapping the pipes and turbo can reduce underhood temps but you may get too hot for say a DC or pacesetter and they may warp or crack... also the DC and Pacesetter use thinner gauge flanges and primaries which can warp or crack.

[ICEMAN707]

i dont see how a turbo could get as hot being away from the head like that in a downpipe setup. the header should be the one that's taking all the heat just like it was without the turbo.

another idea i had was a B-series jackson racing supercharger with a custom A-series flange and custom pulley setup...but that's an expensive risk project to hack a jackson racing supercharger flange and weld in a custom A-series flange to it to fit the A20A3. if i had money to burn, i would try it....then again maybe not, instead maybe get a 97-01 prelude type SH and supercharge it and be done with it.

[AccordEpicenter]

that turbo sitting where the battery is would probably put out enough heat to fry all the wiring within 6-8" around it. If you could shield it and package it effectively its not a bad idea, the problem is that with using the stock header it still has to make a 60 degree plus turn from the bottom of the manifold to come back up to the turbo, and youll lose more power than its worth. To do this effectively, youd need to make your own manifold and custom runners. Turbos are most efficient when they are VERY HOT, so ideally you should keep the runners not toooo long. I dont think the exhaust velocity will be a problem if the manifold is properly designed with a good flowing collector. Using a pacesetter header or dc header etc will simply not work, the primary tubes wont last long and will probably melt under the extreme heat/pressure of a turbo manifold.

[Justin86]

Yea but you are just going to have a bigger mess of piping all over the place to put the turbo over there, esp with our engine/tranny layout.

[AccordEpicenter]

yeah... i dont think the benefits outweigh the drawbacks...

[A20A1]

i dont see how a turbo could get as hot being away from the head like that in a downpipe setup. the header should be the one that's taking all the heat just like it was without the turbo.

When I was talking about heat issues it was aimed at the header not the turbo... I was referring to someones suggestion of using DC or Pacesetter as a base... the heat would be too much for the gauge of metal used.

not so much the length of the primaries but the fact that the larger tube diameter of the downpipe will cause a drop in velocity... thats why primaries that end closer to the turbo keep there velocity longer and will probably create ( more power / less lag ) that sort of thing.

The Probe is 6 cylinders so it has more exhaust to draw from and will probably be less noticable than a 4cyl.

Other then that wrapping the pipes and turbo can reduce underhood temps but you may get too hot for say a DC or pacesetter and they may warp or crack... also the DC and Pacesetter use thinner gauge flanges and primaries which can warp or crack.

another idea i had was a B-series jackson racing supercharger with a custom A-series flange and custom pulley setup...but that's an expensive risk project to hack a jackson racing supercharger flange and weld in a custom A-series flange to it to fit the A20A3. if i had money to burn, i would try it....then again maybe not, instead maybe get a 97-01 prelude type SH and supercharge it and be done with it.

you don't need a custom flange for the Jackson... youy just need to modify it like you would a B18 B16 manifold.

[SteveDX89]

I think the main reason for that design is so a single turbo could be used on a V engine.

[Robs89LXi]

yeah... i dont think the benefits outweigh the drawbacks...

For me it would. Like I said, I've got to keep my A/C and cooling fans, so realy, I don't have much of a choice. It may not be the most efficient system, but oh well, it still should produce good power. If heat is the only issue, that can be managed. Keeping the A/C, having the turbo in much more accesible location, and having more options for turbo size makes it well worth it to me.

[Robs89LXi]

Turbos are most efficient when they are VERY HOT, so ideally you should keep the runners not toooo long.

Why would they be more efficient when hot? If this is true (and I'm not disputing it, just figure there is something I'm missing here), then why are they oil cooled, or even oil/water cooled? I know of some guys that even use inline oil coolers for their turbo oil supply.

[A20A1]

Turbo heat doesn't make it efficient... it will kill the turbo faster... What you mean is the Hotter exhaust makes it efficient because it's the heat that keeps the exhaust energy high, since less energy is converted to heat and allowed to bleed from the pipe as wasted energy when you contain it.

[Robs89LXi]

LOL. Yeah, that is what I thought he was refering to. Hot exhaust gas is less dense, so flows faster, thus causing quicker spool up and turbine speed. Still, I think the loss on a system like this would be very, very small, if not negligible.

[AccordEpicenter]

yeah thats what i was referring to rob... sorry for the confusion. I think if you designed it correctly the losses from the slight reduction in heat would be negligable, but i dont think that could happen if you used the stock exhaust manifold. I think the best example of a good execution of this idea is Accordtheory's manifold... Runner length doesnt seem to have soo much of an effect on performance as does runner volume and merge collector flow.

These are nice too



Accordtheorys manifold (right) has nice runner length and looks like it should flow decent. The one left of that is very nice too but i feel the runners are a little too long for optimum performance.

[A20A1]

Id be worried about spark plug access though... all but one of those seem a little tight. It be nice to have a DOHC motor and not have to worry about it.

[ICEMAN707]

i like that stainless steel turbo manifold. whose is that? i want one! hehe. anyways, how about the jackson racing supercharger idea? could that work with some custom pulley and belt bracket setup?

[AccordEpicenter]

i like that stainless steel turbo manifold. whose is that? i want one! hehe. anyways, how about the jackson racing supercharger idea? could that work with some custom pulley and belt bracket setup?

thats for a ZC engine and it cost well over $1000 to have made. Yea you probably could get the supercharger to work, but you guys have to realize youll need a nice big custom header to complement this, a dc sports or pacesetter header is optimized for n/a apps, and quickly limit your power output on a forced induction setup.