Quote:
Originally Posted by Def
In your opinion, what's the best EFR for a well flowing SR20DET - figure VE head for the ultimate SR head flow - for track usage.
-~450 rwhp track power level (so reasonable efficiency all across for heat reasons).
-Roughly 470-500 rwhp range on the street in "kill mode" running it off the map a bit if necessary.
-Powerband should be at least 4-8k RPM, and it'd be better if a few hundred RPM on either side is also nice and strong (so 3.7-8.5k RPM as a wish powerband).
I don't know if the 6758 has got that much oomph in it, but it's a 53 lb/min turbo, so maybe it does? Seems like it'd be awesome response... My only concern with that is I've had a horrible time keeping T25 inlet gaskets to last on track. The M8 studs creep just enough (even stock Nissan inconel ones) that the gasket starts going, then it's all over. I'm betting a TS T4 would hold up better, but I still think a v-band inlet is the easy button for reliable track usage and easy serviceability. 7163 should definitely do the power levels, but roughly where do you think an SR is going to spool it up?
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-I agree that positive EFR results continue to come in, and it's largely due to the fact that BW is SHIPPING the turbos. When our customers get the turbos, install them and see the performance and durability are as promised we can rest easy. Fortunately i have not heard of any disgruntled/upset EFR customers in quite a long time
-What fuel are you using on your build? (sorry if i missed it)
-considering your needs for the application which you are describing -- I think a 0.80 a/r twinscroll T4 7163 would be the bee's knees. Thats what i am thinking to setup my redtop as (with a VE head swap). It should have zero difficulty delivering an absurdly broad powerband from 3500-85000rpm.
-If you use our M10 hardware with Heicolock washers and high temp Antiseize, your hardware will stay in place for a long long time, no issues (this hardware comes with our manifolds and kits). M8 hardware is just not as robust or durable. the vband configuration does have it's benefits, and a larger 0.85 A/R for those who plan to run the turbo to the limit is one of them. Vbands are great from a convenience standpoint, but twinscroll IWG is the way to go IMHO!! and its really much easier to service M10 studs on a T4 footprint compared to M8 on a T25 foot
-Id rather not make any guesstimates of spoolup on an SR for singlescroll or twinscroll.. everything ive seen looks the part so i think its just best to wait and get some results first as a benchmark
-I still think the EFR6258 is the bomb-diggity for a stock SR20!! anyone with a basic sr and 2871 or otherwise that can do a back to back for one of these smaller EFRs will be ecstatic
Quote:
Originally Posted by LuckyX2
This is a pretty important question for me, because its a $400+ difference between internal and external on a twin scroll setup. Geoff, any back to back IWG vs EWG dynos on an EFR that you're aware of? I'm sure the externals are better but if the internals are close then I'll put the $400 towards something else.
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I dont know of any IWG vs EWG back to back comparisons that would answer any questions vs raise more questions - but there were significant efforts invested to ensure that the EFR was "aerodynamically optimized" for minimum losses. Truthfully, I dont think there is any downside to the IWG aside from the smaller A/R and the single port actuation... also Turbosmart is releasing a push/pull IWG actuator for the EFR. not that my plans should have any bearing on your build or specific needs, but I prefer IWG on the cars/engine setups I build for myself
Quote:
Originally Posted by LuckyX2
The 6758 just isn't going to have that top end flow since it maxes out at 7lb/min less than the 7163. Given that Geoff just confirmed the 7163 spools similar to a 6758, I can't imagine buying anything other than the 7163 for a 550whp or less build.
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youve got a good understanding of this and how to use the matchbot web page. I agree with most everything youve written, thanks for chiming in.
Quote:
Originally Posted by Def
If the 6758 will do near 500 rwhp in kill mode - then I'd be fine with it. I'm all about pushing a compressor to the max to get the best powerband possible. I don't really need a 550 rwhp turbo since I don't see the car ever having the fuel to do that on E85 or wanting to push the transmission I've got that hard. But if the 7163 is the ticket to making above 450 rwhp, then that's obviously the way to go.
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The 6758 does have slightly lower inertia, and the lab guys tell me there is a spool benefit as a result. The indycar guys indicated there was no downside on the higher inertia 7163 in a 0.85 a/r compared to their 0.85 a/r 6758 but it's still a bit early to know how it will all play out on a 4 cyl engine - and undivided VS twinscroll. There is a lot of learning to be done. Plus we are developing a few other housing ideas to try out on
Quote:
Originally Posted by PoorMans180SX
I've seen quite a few cars make nearly 10hp per lb/min on E85 (in person on a mustang dyno). If the EFR series is like the Airwerks series (which would only make sense), then they will keep making power even in the 30-40psi range. I don't see why a 6758 couldn't make 500whp in kill mode on a well modified SR, especially on a dynojet.
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I agree that 10hp for every lb/min is attainable on an efficient high-VE setup. However I have not seen any EFR6758 exceed 450whp, I believe that HP limit is due entirely to the turbine housing's 0.64 A/R. The new 0.85 a/r housings will likely allow for the increased compressor flow to be used in it's entirety... I am eager to try that out for the 6258 also.
have a great weekend!!