at what point should i consider an external wastegate?
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How big is the steath turbo??
got any turbo identification numbers so we know what chu are talking bout??
got any turbo identification numbers so we know what chu are talking bout??
Not a waste of money but rather a solid performance improvement on the THDP. Modify the crossover and put the WG on there. What's a THDP cost? An ATR SS DP with no WG is $300, buy a used WG and weld the flange onto the X-over pipe.
Think of it this way, all the exhaust gas has to crowd the turbine before it is evacuated. With the external on the X-over, the gases don't have to crowd the passenger side cylinder bank, less backpressure.
The THDP obviously works, but so does this method. Cleans up the engine compartment too!
Think of it this way, all the exhaust gas has to crowd the turbine before it is evacuated. With the external on the X-over, the gases don't have to crowd the passenger side cylinder bank, less backpressure.
The THDP obviously works, but so does this method. Cleans up the engine compartment too!
I'm running a TE44, stock IC with Dutt neck and 40# injectors. I'd thought of the same thing, running an ATR or TH DP with external WG, possibly a Racegate. I know it's a little bit of overkill, but if I can get the setup for a good price, is it worth it?
I would be very interested in any documented performance improvements of an external gate over the THDP with an internal gate on anything but an all out race car......
if you "clean up the engine compartment" by putting the gates on the crossover, that is going to be all kinds of fun to adjust them. By the time you buy a downpipe and wastegate(s) it will be much costlier than the THDP. Plus, you are adding another source of problems to your car (particularly if you buy used or inexpensive, ....)
An external gate works well with the high dollar electronic controllers that many "serious" racers use
I just can't agree with the "backpressure" theory either...once the exhaust system is full, the main source of backpressure is the turbo and an upstream wastegate won't change that...it'll just bleed off total boost
if you "clean up the engine compartment" by putting the gates on the crossover, that is going to be all kinds of fun to adjust them. By the time you buy a downpipe and wastegate(s) it will be much costlier than the THDP. Plus, you are adding another source of problems to your car (particularly if you buy used or inexpensive, ....)
An external gate works well with the high dollar electronic controllers that many "serious" racers use
I just can't agree with the "backpressure" theory either...once the exhaust system is full, the main source of backpressure is the turbo and an upstream wastegate won't change that...it'll just bleed off total boost
backpressure in the turbine housing....hmmmm...seems to me, once you get to your boost, the backpressure will equalize throughout the system....you just beed enough out of the gate to keep your boost (aka backpressure) at a certain level ( no matter where the gate is.....)
I understood the reason for putting gates on the crossover was you can sometimes get better control...most gates are after the turbine (internal or external)
I can't argue with you 'cause I am no engineer, so maybe someone has some facts at hand?
I understood the reason for putting gates on the crossover was you can sometimes get better control...most gates are after the turbine (internal or external)
I can't argue with you 'cause I am no engineer, so maybe someone has some facts at hand?
azgn, what do you use?
does a th dp control the te45a? do you have a stock style actuater or a hd. my whole thing about this is because my t top car witha turbonetics stage 5 (te60) cannnot get boost over about 16-17 psi(stock actuater) no matter how much i adjust it(i think i need a new actuater) i am scared of the bleeders, but was considering the ramchargers btsc. i was weighing these opitions for my hardtop car
does a th dp control the te45a? do you have a stock style actuater or a hd. my whole thing about this is because my t top car witha turbonetics stage 5 (te60) cannnot get boost over about 16-17 psi(stock actuater) no matter how much i adjust it(i think i need a new actuater) i am scared of the bleeders, but was considering the ramchargers btsc. i was weighing these opitions for my hardtop car
Intercooler
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I am in the process of making the switch. On a large turbo I think the external would be a better option if you use a decent gate like a Racegate (what I am getting). I didn't do it just for that though. It makes swapping "any" turbo on the car a snap! I was fighting a stock actuator and brackets so now I don't have to worry. On a turbo flowing 900+ CFM sudden WOT to boost levels over 20 PSI I think will be in more control with an external.
I have a HD actuator with a THDP and control my boost manually (loop the compressor & WG) with the tension on the arm...works very well
I imagine with a bigger turbo I too would go to an external gate and controller to get accurate boost control at launch, etc
My setup works fine for what I am doing and the boost stays steady
you can wire the WG shut and see if the actuator is the culprit (just be careful not to let the boost get away from you)
I imagine with a bigger turbo I too would go to an external gate and controller to get accurate boost control at launch, etc
My setup works fine for what I am doing and the boost stays steady
you can wire the WG shut and see if the actuator is the culprit (just be careful not to let the boost get away from you)
It wouldn't make any more difference on a race car vs. a tractor, backpressure is backpressure.
I don't know about difficulty working with it. I take (2) ½" nuts off, disconnect (2) hoses and it's off. I've rebuilt mine in the trailer between rounds. Can you service your THDP that easily?
I have a bleeder valve and can EASILY keep it to within 2 #'s at the worst on shifts. It has excellent command of the boost.
You've almost got it. The wastegate will bleed off un-necessary exhaust gases AHEAD of the largest restriction. The effect is that the restriction is minimized. You have to pile all those gases through there no matter if they're going to drive the turbine or not. I only send what is required to that restriction. The largest beneficiaries would be the passenger side cylinders.
As far as cost goes, I think I've got less in mine than what a 3½" THDP goes for. I know the THDP works, it's just that I feel there are better ways to do it. How do the PRO 5.0 cars handle it?
I have a Te45A on my car with a Mease down pipe and a heavy duty stock style actuator. I still have my waste gate solenoid hooked up and controlled by the Extender chip. I set my boost level with the rod on the actuator. I can honestly say that I have had no boost control problems with this turbo and actuator compared to my stock turbo and the TA49 and the stock actuator.
The thing I noticed with the TE45A is that once it builds boost, it will go instantly to whatever I have it set to where as the stock turbo and TA49 would both ramp up gradually.
I know of a lot of guys who run stock style wastegates with much larger turbos with no issues. Some guys think that adding external gates are the end all or that they are gaining performance. IMHO, there is nothing to gain unless you are experiencing boost creep and this is taking into consideration that you dont have the rod on the actuator too tight/short.
A single Deltagate would be barely adequate with a TE45A. If you run a Deltagate, you will need 2. I also agree that mounting on the cross over is a no no. You want the waste gate as close to the turbo as possible. I seem to remember this being mentioned in Corky Bell's book.
The thing I noticed with the TE45A is that once it builds boost, it will go instantly to whatever I have it set to where as the stock turbo and TA49 would both ramp up gradually.
I know of a lot of guys who run stock style wastegates with much larger turbos with no issues. Some guys think that adding external gates are the end all or that they are gaining performance. IMHO, there is nothing to gain unless you are experiencing boost creep and this is taking into consideration that you dont have the rod on the actuator too tight/short.
A single Deltagate would be barely adequate with a TE45A. If you run a Deltagate, you will need 2. I also agree that mounting on the cross over is a no no. You want the waste gate as close to the turbo as possible. I seem to remember this being mentioned in Corky Bell's book.
Woody - I gotta agree with Nashty here. If I can reword his argument a little bit:
-the power the turbine extracts from the exhaust gas is a function of exhaust mass flow, EGT, and the ratio of turbine inlet to turbine outlet pressure. If you keep the flow and temperature the same, but decrease the turbine outlet pressure (or increase the turbine inlet pressure), you will extract more power from the exhaust, which will turn the compressor side faster, which will try to increase the boost level.
To keep the boost level the same, you have to change something. Realistically we can change the exhaust flow through the turbine, or we can change the inlet/outlet pressure ratio. When the wastegate opens further (in reaction to the rising boost pressure) both of these things happen: A. more exhaust flows through the wastegate, so less flow goes through the turbine, and B. the pressure in the headers drops some, lowering the inlet/outlet pressure ratio.
-Note that last bit: lowering the pressure at the turbine outlet also lowers the pressure at the turbine inlet, which is the backpressure in the headers. Lower backpressure there = more power.
-Lots of mods we do has this effect. Remove the cat - lowers the pressure at the turbine outlet, which lowers the backpressure in the headers, which gives more hp. Same thing with better mufflers/pipes (or no mufflers/pipes). Same thing with a THDP. vs a stock downpipe.
- If you go from a high restriction elbow/downpipe (ie stock) to a low restriction elbow/downpipe (ie THDP), you get this effect. If you had the same high restriction elbow/downpipe, but passed less exhaust through it, you would also see a lower pressure at the turbine outlet, which would drop the backpressure in the headers. This is where a wastegate on the crossover can come into play.
In the integral wastegate case, all the exhaust goes all the way up to the turbine housing, and when wastegated is just stuck right back into the turbine outlet. The headers and downpipe see the entire flow, and have the maximum pressure drop. If you put a gate on the crossover and dump it to atmosphere, or after the downpipe, the pass side header and the elbow/downpipe don't see the entire flow, and so have a lower pressure drop than before. Even if it is a low restriction piece (ie THDP), the pressure drop through it is still less, since the flow is less. And that means the turbine outlet pressure is reduced, which means the header backpressure is reduced.
Now, it should be obvious that the more pressure drop you have in the elbow/downpipe, the more of an improvement you'll get by having an external gate on the crossover. On a mild car, you might see a big jump on a car with a stock downpipe, but no measurable improvement if a THDP is in place. On a race car, maybe a guy with a 3" THDP sees a gain while the guy with the 3.5" THDP doesn't. Just depends.
Back in '89 or so, Car Craft had some EFI car shootout, and Duttweiler had 2 GNs there, the faster one running low 12's maybe. In the buildups he mentioned that he had an external gate on one of the cars (both had stock downpipes of course). He said it dropped the backpressure by 8 psi and was worth ~20 hp.
John Estill
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