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Wastegate location?

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Old 12-26-2003 | 12:11 AM
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Default Wastegate location? PICS

I`m in the process of fabing up a new 2.5in crossover to replace the 2in one. The crossover will be routed like the Qmp one, instead of in front of the well on the oil pan. What i`m wondering is should i mount the wastegate on the driverside of the crossover where it was or on the pass. side by the manifold where i can tuck it up out of the way.
I also just finished the 2.5in pipe from the turbo to the intercooler. Instead of routing it around the edge of the radiator I cut a hole in the air dam and routed it under the radiator and up into the intercooler to minimize bends, turned out really nice. First drive after the cooler pipe, The car seems to pull harder and more consistent up to 6000rpm instead of feeling kinda flat. But that could just be the cool weather. i`ll try to post some pics of the piping tomorrow.

Last edited by MYTURBOT/A; 12-29-2003 at 01:08 PM.
Old 12-26-2003 | 12:53 AM
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If there is any way possible, you really should try to mount the wastegate AFTER all 8 cylinders. You could run a 2" pipe off the log manifold to the wastegate from the 90degree downward bend the log makes dumping into the turbo (follow me?). If you re-locate the ABS box, you could mount the wastegate in that general area very easily. Even easier if you just want to do away with the ABS all together, but not necessary. This is what I did with the T88 on the Z and it worked out nicely.

Good luck and Happy Holidays!
Old 12-26-2003 | 09:47 AM
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I think a 2 1/2" crossover is overkill and will hurt you. You velocity is going to slow way down. You got to think there is such a bigger restriction in the turbine housing so the crossover is not gonna hurt. My planned 1500 HP motor only uses a 2 1/2" If you look at all the big guys, they try to run a small header and small cross over to keep the velocity up. Most of the SSO mustangs only have a 1 3/4" header w/ 2 1/2" crossover.
Old 12-26-2003 | 10:33 AM
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Thanks guys. Rob what would i have to do to remove the ABS pump? Can i just remove the pump and install a proportioning valve, or is there more to it?
Old 12-26-2003 | 11:12 AM
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i think your idea of mounting the wastegate to he pass crossover would be neat and clean and easy.. and just vent it to atmosphere.
Old 12-26-2003 | 11:13 AM
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Rob if i do decide to tap the wastegate into the manifold at the bend, How long is to long for the pipe that connects the gate to the manifold? without removing the ABS the pipe would have to be about 13in long is this to far away from the manifold? Thanks for the help.
Old 12-26-2003 | 01:25 PM
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I agree with Rick C5.... i don't think the larger crossover is going to help much... that is not the restriction of that style kit.

But if you are still planning on running the log manifold.... then keep the wastegate on the crossover... if you really want to make the kit right.... and make a driver side header and "Y" it together just before the turbo, and then put the wastegate after all 8 cylinders.

he he.... and yea i second the vent to atmosphere... doesn't impede the downpipe flow and sounds purty wicked when it opens up
Old 12-27-2003 | 08:11 PM
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Why in the world would you want to keep the WG on the crossover in between the two banks of the engine?? That makes no logical sense at all! We keep discussing this, but you have yet to provide an explanation as to how this is better than venting after all 8 cylinders. I don't think it's a good idea to recommend the wrong thing to someone just because you are trying to make a point to me. Especially when between the two of us, I'm the only one that has real experience with both WG locations on an LS1.
Of course it would be better if he had a tubular turbo manifold. Have you actually ever tried to build one to fit the F-Body??? And then fit the "Y" pipe also?? In a perfect world, that would be great. He/we are working within very confined areas. You do what you have to do. He's trying to make the kit better without starting over from scratch!
BTW, we made 1000Hp with that restrictive log setup and never as much as hiccupped. So why is it so bad? We've already proven that it can provide the HP over and over again. I'm even re-proving it on a daily basis right now with the Formula. So unless you want to make more than 1000HP, spend twice as much money, or cut up your frame, why would a tubular manifold be necessary?

The ABS can be removed by running new lines to the master cylinder. Actually a pretty simple job. I believe there may even be a kit offered by one of the Sponsors of this Board? If you remove the ABS, you should be able to keep the WG length down to about 5-6", which will work fine.

Trust me, this is the way you want it.
Old 12-27-2003 | 09:28 PM
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Yep, ideally the wastegate pipe will be directly before the turbine inlet flange.

When it is mounted on the crossover, it forces some of the exhaust gases from the drivers side of the engine to flow backwards through the exhaust system.

Mine is approx 10in long before it attaches to the wastegate, and now actually goes back 5ft 10in (from the gate) before merging back into the exhaust system.
Old 12-28-2003 | 01:20 AM
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Why in the world would you want to keep the WG on the crossover in between the two banks of the engine?? That makes no logical sense at all! We keep discussing this, but you have yet to provide an explanation as to how this is better than venting after all 8 cylinders. I don't think it's a good idea to recommend the wrong thing to someone just because you are trying to make a point to me.
I have already explained this 3 times on the "other" site.... but i will say it again briefly for the 4th time in simple terms. George at turbotech put the wastegate there for a reason. Because the TT kit was the only turbo kit in existence for the Ls1... he went with the log style kit as a "street" kit.. he knew it's limitations, but because there wasn't another turbo kit out to compare too.... it wasn't a problem.
Having the wastegate there does indeed cause some exhaust to flow backwards as INTMD8 said, however it relieves a ton of exhaust flow out of the system and prevents it from congesting the log manifold. Once full boost is reached... all of the extra exhaust can bypass the log on the TTi kit, but can not on the QMP kit.

Especially when between the two of us, I'm the only one that has real experience with both WG locations on an LS1.
You went 9.8's with a modified TTi kit making 700rwhp, then spent a ton more $$ and time, made the QMP kit... went 9.8's making 700rwhp. Yea, moving that wastegate was definitely the way to go

Have you actually ever tried to build one to fit the F-Body??? And then fit the "Y" pipe also??
actually yes, i have been working on that in my spare time. It is going to take some longer lt1 wires and a coil relocation on the driver side, an alt relocation to the same spot the QMP and TTi kit have it and an Ati fan set-up( to allow room for the turbo) but i have alot of the piping mocked/tacked up... just need a TIG welder to really do the job right. The ABS might need to be slighty shifted... all the stock lines/wiring will still work, just have a different mounting bracket in mind.
It is sort of a copy of the Lt1 PTK kit..( http://www.proturbokits.com/LT1%20kit%203.JPG) just modified to fit around the Ls1 and an air-air cooler. And of course the wastegate will be after all 8 cylinders since that kit is correctly built. There is also enough room for a full 3" downpipe without any dents in it.

BTW, we made 1000Hp with that restrictive log setup and never as much as hiccupped.
Please post the dyno graphs

I'm even re-proving it on a daily basis right now with the Formula.
Did you ever put valvesprings on that car and fix the falling graph? If so please post up the new graphs.


Between the two kits, i say, save a ton of money, get a TTi kit with the t76 upgrade... put a precision 63 on there, run 9-10 psi and with good tuning the results will be similar.

Lastly... i see exhaust A/R's of 1.3 are now being recommended? I guess the combination/issues of the log manifold and on-center exhaust housing is trying to be offset by running a huge A/R?
Old 12-28-2003 | 02:20 AM
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I have already explained this 3 times on the "other" site.... but i will say it again briefly for the 4th time in simple terms. George at turbotech put the wastegate there for a reason.
Okay, but you still haven't told us that reason. For the FOURTH time now!

Because the TT kit was the only turbo kit in existence for the Ls1... he went with the log style kit as a "street" kit.. he knew it's limitations, but because there wasn't another turbo kit out to compare too.... it wasn't a problem.
Okay, so let me get this straight. If you do something wrong, but there is nothing else out there to compare it to, "it's not a problem"???? Hmmm...more great reasoning from you.

Having the wastegate there does indeed cause some exhaust to flow backwards as INTMD8 said, however it relieves a ton of exhaust flow out of the system and prevents it from congesting the log manifold.
...And dumping it after all 8 cylinders WOULDN'T release a ton of backpressure??? Also, can you tell us exactly where all of this exhaust gas is "congesting" in the log manifold??

Once full boost is reached... all of the extra exhaust can bypass the log on the TTi kit, but can not on the QMP kit.
So we all understand you correctly...you are saying that with the TT kit all of the backpressure from the passenger side of the engine can be relieved through the incorrectly located wastegate, but the driver side of the engine cannot since the wastegate is before those 4 cylinders?? Wow....that's exactly right. We finally agree on something.

You went 9.8's with a modified TTi kit making 700rwhp, then spent a ton more $$ and time, made the QMP kit... went 9.8's making 700rwhp. Yea, moving that wastegate was definitely the way to go
Yea, it was all the wastegate location . Once again, you have everything wrong. My car never went 9's with the TT kit. It went 10.89. The ONLY thing that remained of the TT kit when I did go 9.94, was the log itself. Not the primary tubes, not the crossover, IC piping, downpipe, intercooler, turbo, wastegate, or blow through MAF. None of it! We only reused the header flange (of which we opened the holes up to 1 3/4") and 2 3/8" straight piece of "log" pipe. If you call that a "modified TT kit", so be it.
I then added over 200lbs to the car, took away 30 cubic inches, put on our complete production kit and went a tenth quicker and gained 2mph in the 1/4. So what's your point?

There is also enough room for a full 3" downpipe without any dents in it.
There doesn't have to be a dent in it. Only if you want to be able to steer the car, that's all. Wow, now that you point it out, imagine how much more power our kit would make without that restrictive dent!

Please post the dyno graphs
I have already answered you about that 3 times. So I'll try to speel it out for you: big turbo (T88) + loose converter (4000 stall) + non-loadable dyno (dynojet, not Mustang Dyno) = no dyno sheet Get it yet?
But guess what...I have TIMESLIPS!!! 141mph timeslips! You calculate it out genius and let me know what YOU come up with.
You know, they can't dyno Top Fuel cars either, but they can still tell you how much HP they make. And how do they do that again??

Did you ever put valvesprings on that car and fix the falling graph? If so please post up the new graphs.
Nope. Valve springs have been on order for about two weeks now. Trust me, as soon as I get them, I'll have it back on the dyno with some new record setting numbers.
Is that the best you can do is point out that the 120,000 mile stock valve springs are too weak to hold high rpm HP? It still made 580rwhp on pump gas with a 120,000 mile stock engine? Maybe I should move my wastegate to where the TT WG is? You know, to keep all of my exhaust gasses from "congesting". What do you think?

i see exhaust A/R's of 1.3 are now being recommended? I guess the combination/issues of the log manifold and on-center exhaust housing is trying to be offset by running a huge A/R?
What do you have against on-center exhaust housings? Of course tangental is better...so what, who doesn't know that? You'd think you discovered it or something the way you keep bringing it up. And you'd think I invented the on-center housing the way you keep complaining about it! Do you email Turbonetics daily and tell them how it's not as good??
When did we start recommending different, larger AR housings? Well...when the engine requires it. Larger displacement, larger turbo, etc.. Maybe you should email Precision Turbo and ask them why the largest AR exhaust housing they offer for their T74 is a .85? And maybe you should get off my back and mind your own business. Just my opinion though. Then again, maybe it's not just my opinion. I thought you had already been warned by the Mods to stay out of threads involving me?
The way I see it, MyTurboT/A was appreciative of my help before you jumped in and started your usual ranting/stabbing.
Old 12-28-2003 | 03:11 AM
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Wow that was interesting? I have the crossover done but havent decided if i want to pull the log to mount the wastgate might just mount it on the crossover untill i get the stuff to remove the ABS.
Having the wastgate vent only one bank does relieve backpressure for the pass side bank but it also throws the engine out of balance from uneven backpressure. I personaly don`t think the log is much of a restriction. It`s obviously not as efficent as a header style manifold but is still sufficent for our application.
FWIW I asked george about moving the wastgate and he told me to try and move it after all 8cyl. To the bend where rob just mentioned moving it to. He said the reason he placed the wastgate in the crossover was for simple mounting and instalation. In fact he said the kit was only designed to run 6-8psi and after that people might start seeing boost creep because of the wastegate location. Thanks for the help rob i`ll try looking through the sponsors for that ABS delete kit.
Old 12-28-2003 | 08:44 AM
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It's a shame that you have to keep dealing with folks that throw out bad info Rob. Hang in there!

Eventually, the debate will begin as to why the QMP aftercooler doesn't reduce outlet temps below ambient like the others do....lol
Old 12-28-2003 | 11:48 AM
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mount one after the log and one on the crossover.. best of both worlds

i think the only way you are going to not have a boost problem with the w/g after the log is to do something like oversize the exhaust housing. if you want to keep the one you have i would at least try a crossover mounted wastegate.. heck i have 2 junk crossovers here off my qmp kit that didn't work that you can HAVE to fool with if you want.
Old 12-28-2003 | 02:31 PM
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Mightymouse - why is it that you have "two junk QMP crossover's"? Weren't those supposed to be sent back to us?

Well all I can say is this:

Our kit works. It works very well. It has more documented miles on it than any other kit out there that I am aware of on a stock engine (over 30,000 daily driven, and raced miles so far)
Our kit has put down the fastest 1/4 mile time to date (and held that honor for over 2 years now!).
Our kit has made more HP and TQ than any other F-Body kit available.

So calculate all you want with theories. These are the FACTS.
Old 12-28-2003 | 09:21 PM
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Originally Posted by Rick C5
I think a 2 1/2" crossover is overkill and will hurt you. You velocity is going to slow way down. You got to think there is such a bigger restriction in the turbine housing so the crossover is not gonna hurt. My planned 1500 HP motor only uses a 2 1/2" If you look at all the big guys, they try to run a small header and small cross over to keep the velocity up. Most of the SSO mustangs only have a 1 3/4" header w/ 2 1/2" crossover.
me to add some fuel to the flame, but my 2.5" X-over works great!!!
i think i spoolled faster, i make my 10psi at 2650 RPM with my cutout open and 2800rpm (i thnk, might be 2900rpm) through full exhaust. i thought the main weakness of the TT kit was the crossover, with they impoved, then that intercooler (i want lower IAT!!)

great idea on the IC pipeing, get them PICS up!!
i want to do that , but am wanting till i can get a better IC
Old 12-28-2003 | 09:28 PM
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I was going to call George at TT and ask him, but my feeling was that the location of the WG was dictated by space constraints and lack of time.
Old 12-29-2003 | 01:49 AM
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Ok here are some pics lighting was kinda crapy but there not to bad. I finished everything up tonight and checked for leaks. I ended up putting the gate on the crossover for now but positioned it so it`s easier for the exhaust to exit.
Attached Thumbnails Wastegate location?-car_0023.jpg   Wastegate location?-car3_0024.jpg   Wastegate location?-car1_0022.jpg   Wastegate location?-car7_0017.jpg   Wastegate location?-_0018.jpg  


Last edited by MYTURBOT/A; 12-29-2003 at 02:16 AM.
Old 12-29-2003 | 02:34 AM
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Well just got back from floging the car and all i can say is damn. This thing moves I`m making 9psi by 2600rpm was 3000. The wastgate is definatly doing a better job of controling boost in it`s current location. previously it would drop from 9psi down to about 7.5-8psi now it stops dead at 9psi and don`t drop at all not even a half a psi, which is surprising. Definatly a good mod switching to the 2.5in crossover and changing the wastgate location. The car drives like it should And The engine don`t feel as ruff at high rpms. Hell I can even tell a difference in the exhaust note.
Old 12-29-2003 | 08:11 AM
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glad to hear it.


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