SP Boost Actuated Exhaust Cut-Out for my Greddy EVO TT
08-27-2010, 10:45 AM
#1
SP Boost Actuated Exhaust Cut-Out for my Greddy EVO TT
While visiting SP this week, I decided to take advantage of some of their innovations and went with the Boost Actuated Exhaust Cut-out. My original intent was to install the pair. Due to time constraints and to make life simpler for all, rather than attempt to remove the downpipes on the Greddy Kit (PITA), we opted to install a single dump in between the 1st set of behind the cat pipes seen below:
***(I apologize for any blurry pics, only had my cell phone)***
Before Shots:
After:
First came assembling the actual 3" cut-out with the necessary down facing tip:
Then some more fab work:
Test fitting (Tacked it up):
Then final welding run the boost line and voila:
Done.
I utilized this set-up to counteract the anticipated hp losses I would incur by going with the Cosworth intake. Worked out pretty well. No overall power losses than previous set-up.
***(I apologize for any blurry pics, only had my cell phone)***
Before Shots:
After:
First came assembling the actual 3" cut-out with the necessary down facing tip:
Then some more fab work:
Test fitting (Tacked it up):
Then final welding run the boost line and voila:
Done.
I utilized this set-up to counteract the anticipated hp losses I would incur by going with the Cosworth intake. Worked out pretty well. No overall power losses than previous set-up.
Last edited by rrmedicx; 08-27-2010 at 02:17 PM.
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08-27-2010, 11:22 AM
#8
And the best part about the cut-out, is that it requires NO RE-TUNING!!!!
You heard me right, no re-tuning is required. So if anyone wants to make a quick 30-50 rwhp get the cut-out from SP and have it welded up anyway you can for some cheap hp.
08-27-2010, 11:24 AM
#9
Yeah me to. Shot plenty with Reid's vid camera while he was out of the shop. Hopefully he can upload something soon. You will se a test video we shot with me giving the car some gas and Larry connecting the boost hose to hear the difference of the cut-out on and off. Pretty cool.
And its not ridiculous either. Sound is ground shaking though. Deep Grumble!
And its not ridiculous either. Sound is ground shaking though. Deep Grumble!
08-27-2010, 11:28 AM
#10
When I dyno'd my Cosworth I lost midrange torque, but it picked up above 6000 rpms, just like all the other dynos I've seen (this is compared to a Crawford).
Lots of variables (ignore the comments, both are at 15 psi open loop boost control with no meth), but this type of dyno seems consistent:
So Randy, I think you do lose peak torque, but gain peak whp with the Cosworth, and a flatter torque curve...
Lots of variables (ignore the comments, both are at 15 psi open loop boost control with no meth), but this type of dyno seems consistent:
So Randy, I think you do lose peak torque, but gain peak whp with the Cosworth, and a flatter torque curve...
Last edited by rcdash; 08-27-2010 at 11:45 AM.
08-27-2010, 11:37 AM
#11
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I know a few people that have tested the Cosworth back to back against the stock intake and have all lost HP, one NA - 16 rwhp and one FI - 50 rwhp. On Randy's car I had to take out fuel almost everywhere and a ton above 7000 where it just didnt want to move much air at all. Id keep the stock one with a spacer or just get the CJ one. The CJ is the only one that I can personally say will give you huge gains!!
08-27-2010, 11:42 AM
#13
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When I dyno'd my Cosworth I lost a little midrange, but it picked up above 6300 rpms, just like all the other dynos I've seen (this is compared to a Crawford).
Lots of variables (ignore the comments, both are at 15 psi open loop boost control with no meth), but this type of dyno seems consistent:
Lots of variables (ignore the comments, both are at 15 psi open loop boost control with no meth), but this type of dyno seems consistent:
Looks like you may have picked up 5 rwhp but lost 20 ft lbs or torque!! Not a good upgrade!!
08-27-2010, 11:43 AM
#14
HA, I called it 
looks like excellent idea to avoid using 2 of those 350$ valves! very nice!
so they felt confident that 1 3" dump was enough ,or is that twin 3" pipes to a 4" dump. That would be excellent
Pretty odd that you didnt need a retune based on the advertising dynos that SP uses. There's no way they gained that much power without retuning the car. An extra 50+hp is not a trivial amount of gas because you are tuning in different cells since the boost curve is different
Just curious to as why you dont sell your cossy if your are losing power with it? Too bad Charles wont make his mani with the side mount TB.
on a side note, you said you had to take out fuel. What was the % ETOH in the gas compared to last time? I know the ProEFi is supposed to interpolate, but if the base tunes on either end used different amounts of ETOH, then of course you had to change the fuel table to get the proper interpolation.
looks like excellent idea to avoid using 2 of those 350$ valves! very nice!
so they felt confident that 1 3" dump was enough ,or is that twin 3" pipes to a 4" dump. That would be excellent
Pretty odd that you didnt need a retune based on the advertising dynos that SP uses. There's no way they gained that much power without retuning the car. An extra 50+hp is not a trivial amount of gas because you are tuning in different cells since the boost curve is different
Just curious to as why you dont sell your cossy if your are losing power with it? Too bad Charles wont make his mani with the side mount TB.
on a side note, you said you had to take out fuel. What was the % ETOH in the gas compared to last time? I know the ProEFi is supposed to interpolate, but if the base tunes on either end used different amounts of ETOH, then of course you had to change the fuel table to get the proper interpolation.
Last edited by str8dum1; 08-27-2010 at 11:50 AM.
08-27-2010, 11:51 AM
#15
08-27-2010, 11:56 AM
#16
HA, I called it
looks like excellent idea to avoid using 2 of those 350$ valves! very nice!
so they felt confident that 1 3" dump was enough ,or is that twin 3" pipes to a 4" dump. That would be excellent
2x2.5 inch pipes into 1x3" dump
Pretty odd that you didnt need a retune based on the advertising dynos that SP uses. There's no way they gained that much power without retuning the car. An extra 50+hp is not a trivial amount of gas because you are tuning in different cells since the boost curve is different
We had to re-tune for the Cosworth, not so much for the Exhaust cutout. Larry can confirm.
Just curious to as why you dont sell your cossy if your are losing power with it? Too bad Charles wont make his mani with the side mount TB.
I need it to close my hood. It sits nice and low. With the Cosworth spacer to clear the taller injectors, The crawford was simply too tall. Got rid of my stock plenum many moons ago. And the Cossy is just plain baller. Enough said.
on a side note, you said you had to take out fuel. What was the % ETOH in the gas compared to last time? I know the ProEFi is supposed to interpolate, but if the base tunes on either end used different amounts of ETOH, then of course you had to change the fuel table to get the proper interpolation.
looks like excellent idea to avoid using 2 of those 350$ valves! very nice!
so they felt confident that 1 3" dump was enough ,or is that twin 3" pipes to a 4" dump. That would be excellent
2x2.5 inch pipes into 1x3" dump
Pretty odd that you didnt need a retune based on the advertising dynos that SP uses. There's no way they gained that much power without retuning the car. An extra 50+hp is not a trivial amount of gas because you are tuning in different cells since the boost curve is different
We had to re-tune for the Cosworth, not so much for the Exhaust cutout. Larry can confirm.
Just curious to as why you dont sell your cossy if your are losing power with it? Too bad Charles wont make his mani with the side mount TB.
I need it to close my hood. It sits nice and low. With the Cosworth spacer to clear the taller injectors, The crawford was simply too tall. Got rid of my stock plenum many moons ago. And the Cossy is just plain baller. Enough said.
on a side note, you said you had to take out fuel. What was the % ETOH in the gas compared to last time? I know the ProEFi is supposed to interpolate, but if the base tunes on either end used different amounts of ETOH, then of course you had to change the fuel table to get the proper interpolation.
Last edited by rrmedicx; 08-27-2010 at 11:58 AM.
08-27-2010, 12:11 PM
#18
Thanks for the response!
The cossy is definitely a pretty piece! If you ever change injectors you can go with the short 40ish millimeter Injector dynamics and go back to any plenum you want.
so many neat changes that havent been really document before. Hopefully you guys have boost charts from the initial tune /after cutout as well.
I would guess if you didnt have to tune much for the cutout, that goes to show how free flowing that Evo TT must really be! Possibly since the valve slowly opens you might not get such an abrupt left shift in the boost curve. The charts will be very interesting!
Maybe I will resuse on injen SES exhaust again
The cossy is definitely a pretty piece! If you ever change injectors you can go with the short 40ish millimeter Injector dynamics and go back to any plenum you want.
so many neat changes that havent been really document before. Hopefully you guys have boost charts from the initial tune /after cutout as well.
I would guess if you didnt have to tune much for the cutout, that goes to show how free flowing that Evo TT must really be! Possibly since the valve slowly opens you might not get such an abrupt left shift in the boost curve. The charts will be very interesting!
Maybe I will resuse on injen SES exhaust again
