Borgwarner Twin Scroll 7670 With Dyno Graph
Evolved Member
Joined: Feb 2010
Posts: 1,630
Likes: 4
From: Columbia, MD
Wow, lots of things to take from this... first off, congratulations on getting your car put back together leet. I'm sure you will do extraordinarily well on track with it. Secondly, pretty amazing to get this rebuilt, put back together and dynoed in the short time frame... impressive work from Buschur. Third, I'm just trying to understand this dyno result. It looks nearly identical to the HTA3076 dyno from Dave's other thread in spool and peak numbers, but it does so with dramatically less boost?
It does appear that torque drops off very dramatically on the EFR turbo, far more so than the HTA turbo. Is this similar to the stock frame turbos where the restrictive housing causes excessive back pressure which can spike torque quickly, but it drops off quickly as well?
I'm curious what your feelings are on the turbo are. It seems like its certainly a great setup, and will undeniably be blazing fast road racing. Running nearly 550 whp (Mustang dyno numbers) with only 28 psi seems really good. Is the lack of ability breathing at higher boost really that bad of a thing if its able to do this at that level?
HTA3076, peak boost was 34.1 psi, at 8,000 rpm it had 27.3 psi.
At 28 psi in 4th gear the car makes 539 whp and 480 ft lbs of torque. 20 psi in 4th happens at 3863 rpm. 27 psi happens at about 4379 rpm and by 7898 rpm it is down to 22.27 psi.
I'm curious what your feelings are on the turbo are. It seems like its certainly a great setup, and will undeniably be blazing fast road racing. Running nearly 550 whp (Mustang dyno numbers) with only 28 psi seems really good. Is the lack of ability breathing at higher boost really that bad of a thing if its able to do this at that level?
is the car breaking up Dave? Why is the graph waavy up top? Knock retard?
Do you remember how much HP you lost per degree of timing retard?
Did you not have time to make a 40psi pull?
Do you remember how much HP you lost per degree of timing retard?
Did you not have time to make a 40psi pull?
14.7psi per 1 bar *3.5bar = 51.45psia -14.7atmo = 36.75psig
I suppose I'll wait to hear what the highest boost Dave ran from himself.
I suppose I'll wait to hear what the highest boost Dave ran from himself.
Last edited by R/TErnie; Oct 28, 2011 at 03:00 PM.
Two pictures for you guys. This is a BRAND new engine, put it together, strapped it on the dyno ran 17 dyno runs from 2500-8000 rpm and up to 35 psi of boost. Below is the oil filter after being taken off along with the bottom of the filter container, as you can see both are spotless. The water bottle catch can they have on the valve cover, you can also see, perfectly clean. That's how you build an engine.
This way you seal the CHRA and therefore OILING system from excessive pressure from the turbocharger.
Not all crankcase pressure comes from blow by the piston rings. When running high boost pressures on single dynamic seal turbochargers you get significant blowby into the CHRA and yep...you guessed it...the crankcase.
What I'm saying is... that you'll have less blowbly with this turbocharger and therefore your catch can will stay clean.
And of course you did a great job with the engine, but I wanted to make clear that it's not "all in the engine"
Great 22 page read... Ends in an epic "Happy Ending"..
So the turbo is "responsive", but in retrospect of the back pressure an FPturbo could have done the same with-out the added expenses. David as usual asks the readers to "read between the lines".
Threads like this keep me a fan of Evom.
So the turbo is "responsive", but in retrospect of the back pressure an FPturbo could have done the same with-out the added expenses. David as usual asks the readers to "read between the lines".
Threads like this keep me a fan of Evom.
Great 22 page read... Ends in an epic "Happy Ending"..
So the turbo is "responsive", but in retrospect of the back pressure an FPturbo could have done the same with-out the added expenses. David as usual asks the readers to "read between the lines".
Threads like this keep me a fan of Evom.
So the turbo is "responsive", but in retrospect of the back pressure an FPturbo could have done the same with-out the added expenses. David as usual asks the readers to "read between the lines".
Threads like this keep me a fan of Evom.
Last edited by n2oiroc; Oct 28, 2011 at 06:47 PM.
I know some of you guys are thinking it's a backpressure issue due to the fact it's spooling up so quickly but I wouldn't be 100% on this...
Throw an intake mani on and see what happens
Throw an intake mani on and see what happens