When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It's not about hitting full boost at a particular rpm Or how much power can be put out, It's about usable powerband and transient throttle response. Look a blue's dyno numbers and video,. It's a very nice setup and is doing something similar to what I want.
A stock turbo will never achieve that kind of response.
I disagree.
Like WANKfactor and BLUE TII attest, a stock frame turbo actually will have that kind of transient throttle response which is why I recommended it for an IWG solution. With a series 5 turbine (not the s4 twin-scroll) and only a mild compressor upgrade (say T04B V-trim in factor bored Hitachi comp housing) and properly designed dump pipe (separated wastegate runner), you won't have boost creep issues. The V trim is easily capable of 250-300rwhp at lowish boost, but is still small enough to provide excellent response.
The difference with an EFR7670 is you'll get the same response plus the ability to push the compressor to higher boost throughout the same powerband, meaning broader and flatter torque curve. This won't necessarily benefit you though - with NA higher compression rotors and pump fuel, I wouldn't go above 12psi and the 7670 is only just starting to shine at 14psi. The useable powerband for a 7670 will also be similar to a series 5 hiflow because the EFR7670 compressor hits a wall in the upper rpm as well. The EFR7670 will just produce more torque and more power throughout that entire curve - imagine just pushing the entire curve up. This shouldn't be surprising - a V trim (55mm inducer) is a smaller compressor than a 7670 (57mm) - it should be a very responsive compressor despite the old tech. Same goes for GTX3076R - which is a bigger compressor again (58mm).
A GTX3076R just isn't that sufficiently different on paper from a hiflow Hitachi to warrant consideration IMO. A very expensive turbo and you still need an EWG and the extra fabrication associated with that.
If you're tried the s5 turbo with upgraded compressor and didn't find it satisfactory, I suggest it's more to do with other factors - intercooler and piping, dump pipe design, boost control (electronic boost control can improve boost response considerably), intake etc. That, or perhaps the compressor you used was just too big.
when you say it spools fast off idle, you mean taking off in first gear right? Hell yah it was great then. This was on a first gen so 13x9 wheels, pretty low gear ratios. It was wicked off the line. If I was at any low to mid rpm off boost it took what felt like to long to build boost.
Maybe there were other factors, it was back in the late 90's and I dont remember.
Who sells s5 hybrid turbos these days? Its something I would consider trying again, everyone is saying the same thing about their performance.
I dont really care what turbo I use as long as it gets the job done.
When I talk about transient throttle response, I'm talking about putting your foot down in gear off boost.
When I talk about boost threshold, I'm talking the engine speed at which the turbo is able to develop boost.
It's only once you move to bigger compressor wheels (over 57mm) and compressor housings, that hybrid turbos seem to suffer in this regard. The smaller V trim and Knightsport wheels spool the same as or better than a factory turbo. The factory s5 turbo manifold is also great for spool - nice short divided runners.
I've been tossing up between a hybrid s5 turbo and EFR7670 and the conclusion I came to from my research was that performance was pretty comparable at low boost levels, but the EFR continues to make more power across the whole powerband as you increase pressure. My car is using straight LPG (propane) as a fuel which has similar knock resistance to E85, so I should be able to take advantage of the higher boosting turbo.
The stock hybrid actually had a little better response off idle- it would leave black stripes if you let out the clutch to fast like a V8.
The little T25/T3 sized stock turbo manifold/exhaust housing runners were just too small/high velocity.
mikey D
when you say it spools fast off idle, you mean taking off in first gear right?
I mean letting off the clutch too fast without giving it gas it would leave black stripes like a V8 instead of stalling like a rotary.
Problem was boost would just rocket over 20psi as you approached 3,000rpm with the wastegates full open at 5.5psi (stock cannister) and back then (16yrs ago) I was just trying to break in the engine and tune it on pump gas- so that isn't what I wanted.
The EFR 7670 was really good response too despite being on a "big" T4 manifold and turbo housing, about 5psi or so boost revving it in neutral and 4-5psi boost by 2,000rpm in gear. It was just a little softer 1,000rpm-2,000rpm because of the T4 exhaust housing/manifold.
The ball bearing EFR with the internal compressor bypass valve was especially nice for throttling in and out of boost seamlessly.
It should also be pointed out that you can now get aftermarket fully adjustable canisters for Hitachi turbos - like the ones made by Kinugawa. They are beefier and come with an assortment of springs. Back in the day I remember people doing all sorts of things to help control boost, bending actuator rods etc.
Use the FD RX-7 exhaust manifold/switching valve as a quick spool valve.
And then use an EFR 7163 in the divided 0.80AR T4 IWG exhaust housing with a custom divided manifold.
At low RPM and/or low throttle position have the switching manifold closed so both rotor's exhaust enters a single 0.40AR turbo scroll for lightning quick response.
Then have the manifold open to both turbo scrolls at a set RPM and/or throttle position for the full 0.80AR.
I watched as BNR tried something like this on the dyno one day. I forgot exactly why, but it didn't work out too well. I dont think the flapper was working correctly, and the turbo he used wasn't internally gated. he then switched to some ebay manifold and made 500+ on 93 and water injection.
Thanks for all the info guys.
Its helping my plan evolve into something better than what I started out with.
Im less certain which route Im going to take now though.
I have a really nice first gen car with an e6x, 50mm TWM IDA throttle bodies and 2nd gen ignition on this engine. I was going to sell it to fund my new project but honestly its a pretty good base to build on and I have the cash. The engine was built by mazdatrix for autox street prepared, its a really nice engine. Way less than 1k miles. I really didnt get to do much with it unfortunately, life happened. I was thinking I would be good up to about 16psi of boost on it. Thats slightly less pressure to 18-20 psi on 8.5 or 9 compression rotors, so I felt that my 12-14psi on 9.4 comp rotors on a fresh well built engine was pretty safe.
It also occurs to me that I could sell everything and just get a 4 port, that would be the easier path probably.
Thing is Ill still be looking to hit the same goals, I dont need crazy big numbers in my 2000lbs car.
either a hybrid stock turbo, it would be cheaper route for sure or the 7163, have a better IWG and really crisp throttle response.
Gilgamesh
I watched as BNR tried something like this on the dyno one day. I forgot exactly why, but it didn't work out too well. I dont think the flapper was working correctly, and the turbo he used wasn't internally gated.
Yeah, the manifold would have to have two external wastegates or two internal wastegate passages (like the EFR) for this "quick spool valve" design to work right.
then switched to some ebay manifold and made 500+ on 93 and water injection.
Well, this wouldn't help a 500whp turbo spool anyways because it would just send the compressor into the surge line.
But it could still help turbo response if you kept boost low while operating near the surge line.
When I talk about transient throttle response, I'm talking about putting your foot down in gear off boost.
When I talk about boost threshold, I'm talking the engine speed at which the turbo is able to develop boost..
with my current car, boost threshold is quite low, it makes ~1psi, by 1500 or so, stock 7psi at 2400 and peak boost 13psi at 3200. my friends stock S4 T2 with an S5 turbo hits 7psi about 100rpm later.
with mine the transient is soft, but i have a cat, huge intercooler, and AFM. plus its an S4 turbo!
my last t2 was an S4 with an S5 turbo, and with an open exhaust, stock IC, response was great. no boost control, so only 7psi.
Its interesting, my s4 highflow (57mm inducer) specs kind of unknown but i believe back-cut exhaust wheel, couldnt be described as soft, it was very instantaneous with similar thresholds as described above. That was with (very) large FMIC, 3" exhaust no cat, cast log manifold.
The EFR8374 has similar threshold too, but is definitely softer transient-wise.
In the IndyCar application they initially had issues with the Aluminum CHRA cracking where it mounts to the exhaust housing.
The solution was to make sure it was torqued to spec (not over tightened) and safety wired so the steel fasteners didn't fret the Aluminum and work harden/crack it with thermal cycling.
On the ultimate extremes of an Indy car I can see that being a potential issue. Otherwise I see an aluminum chra as an advantage wrt weight, htx, and so on. Just trying to understand why someone is seeing it as a reason to choose a different turbo instead.
Which btw I proposed the 7163 as the ultimate ultra responsive low-end single turbo choice on RX8Club several years ago and all the RXh8ters came a runnin’ antifa-style ...
mikey D
Im not looking for max power, Im looking for transient throttle response you would want in an autox car. Im ok with power falling off a little on the top end. Im aiming to make at least 225rwhp, I dont imagine I need a crazy high amount of boost, Im thinking 10-14psi
The OP could make his goal power (225rwhp @10psi) on a single primary turbo from the stock FD twins.
7163F compressor map with 76470C compressor map outline imposed on it. Other than the 7670C advantage at the upper high boost area and the larger AR turbine to handle it, they're almost the same for a large part of the map. The far RH side efficiency difference is still only 2% - 4% better for the 7670 ... as long as the engine isn't operating out there continuously it shouldn't be any issue.
I also just saw what I'm assuming must be a new a 4th turbo option for the 7163 now on Full Race; 0.85 AR V-Band with IWG ... $600 adder though, ouch
I also just saw what I'm assuming must be a new a 4th turbo option for the 7163 now on Full Race; 0.85 AR V-Band with IWG ... $600 adder though, ouch
I wrote that page.
All of the EFR Lineup is sold as Supercore + Turbine Housing and they keep ******' with MAP Pricing. If you look at the turbo cost as a whole, it's still FAR more economical than anything from Garrett while being superior in every way.
On my personal turbo kit, I'd use a S5 Turbo II Exhaust Manifold and Turbine Housing and mate it directly to the supercore. Blue TII did this a LONG time ago with his 60-1 and I just finished a setup with an EFR 9174. For anyone interested, shoot me a PM and I'll build you a full kit. :P #AintCare #OEMFitment #PassCAVisualSmog
Pics, Or It Didn't Happen:
Last edited by RGHTBrainDesign; 01-05-18 at 12:17 AM.
I hadn't realized just how far the EFR 7163 surge line swept back at high boost.
So, the EFR 7670 is probably the only EFR turbo in the EFR 7163, 7670, 8374, 9180 range that can run high boost (around 25psi and up) without surging 3,300rpm-4,000rpm on a 2 rotor. EFR 7163 might *just* be able to do it; might have to run without an airfilter.
I also just saw what I'm assuming must be a new a 4th turbo option for the 7163 now on Full Race; 0.85 AR V-Band with IWG ... $600 adder though, ouch
As far as I know they have always had that exhaust housing option.
I plan to use it for the primary turbo on "stock-is-like" sequential twin turbos for my FD with the regular 0.85AR non WG V-band housing on the secondary turbo that comes on the IRL turbos. I believe I have seen that exhaust housing for as low as $450 other places.
That big compressor should surge like a **** though in my mind anything over 18-20psi around 3,500rpm. Looking forward to hear how it works in real life.
Thank god for boost ramping with electronic boost controllers...
Blue TII did this a LONG time ago with his 60-1
Bryan at BNR turbos made the turbo, I just did a bunch of reworking of the turbo and manifold to make it not boost creep on my set-up.
That big compressor should surge like a **** though in my mind anything over 18-20psi around 3,500rpm. Looking forward to hear how it works in real life.
Thank god for boost ramping with electronic boost controllers...
So wouldn't the solution be to run a progressive boost curve? Instead of ramping up as hard as possible, ramp up to the most efficient islands as possible and stay on them. This requires less boost, effectively elongating the duration of both the turbo and motor. It would be easier to evaluate with a turbo speed sensor, I suppose. Damn, I guess I'll order that (relatively gimmicky piece of hardware).
Fitment shouldn't be impossible.
We should talk more about this (somewhere else - I don't want to keep clogging up this thread unless its okay with you guys). I really hadn't considered it a huge issue with surge given the motor is streetported.
That is what I meant, if you want to run boost over 18-20psi you will want to use a boost control solenoid and an ECU boost map to limit boost in the 3,300-4,000rpm range so you don't get into the chugga chugga of compressor surge. 8374 and 9180 are known to compressor surge on the 2 rotor when running high boost and your set-up should spool really fast from my experience.
02-27-17, 07:47 PM
