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100hp per liter SAE from stock S14-B23 2.3

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  • #16
    Originally posted by stevesingo View Post
    Sound's like you are having fun.

    Dyno losses are not a fixed % of a measured power. The greatest factor is road speed as the tyre roller interface is a greater consumer of power than the, prop shaft, diff, driveshafts and their associated support bearings. I trust you are using the same gear, diff ratio and tyres for all E34 tests, and the tie down is the same. In such a case, expressing the loss as a % is not so wide of the mark. But, a different car will have a different loss at a given road speed and more so at a different road speed.

    But, it is not stock.

    -Intake and exhaust custom grind profile based on the cyl head flow I have.( I work with grinder and I love the freedom of making any custom profile I want to try )
    -long tube headers.
    -I custom 3D printed velocity stacks.
    -Hi flow exhaust system (S85 Catalyst converters but placed way behind the trans to reduced back pressure)
    -Haltech Engine management. coil-on-plug
    -Large plastic intake box, same as S14 CF.

    If we are talking external bolt ons, then a header and intake lengths tuned for peak power will help some, but probably kill torque somewhere else in the rev range.

    FWIW, the Evo 2 engine comes the closest to 100bhp/lt DIN at 220hp from 2302cc. I'm pretty sure just a change of EMS to an A/N system would yield 100bhp/lt. On a pre '89 engine probably not as the intake cam is only 248deg.

    What is the cam specs on the S38 engines?
    Hi Steve,

    I get it its not stock as I stated from the beginning. Okay in my mind is somehow stock ))))) bottom is all stock, head is all stock ehh

    If anything the big boy cars will have larger losses, longer drive shaft, larger differential gear 210mm vs 188mm, larger output flanges, heavier tires at 275 rear and also much heavier wheels. When I tested the E30M3 had the OEM 15s. I am very consistent on the tire pressure as well, straps as well. Factory don't lie all of the test I have done is based from factory BHP numbers.

    Yes you can trust me on this I am very specific all the runs to be done on 1:1. US G265 and G280 all test done on the same 4th gear which is 1:1 so no difference there. The dyno owner complains often that I am wearing out his dyno....

    The Stock camshaft intake and exhaust spec on the S38-B35 engine is 248 Degrees same as on S14 US 2.3 and when I ran it thru "Cam-Analyzer" the lift was lost a bit at 10.3mm normal ware also duration.

    Most BMW I have measured the power on this specific Dyno-Jet the gear box, wheels tires, drive shaft length etc they are very very similar as you say similar parts.

    On the E39M5 test. A day before my Dyno appointment I used the same Dyno-Jet 14.7% (my guesstimate was ~335rwhp) drive train loss and here we go it never fails that 14.7% drive train loss. US S62 is rated 395HP SAE - 14.7%=336rwhp on DynoJet. Inside the the video you can note that I used 5th gear as the G420 gear box 1:1 is 5th not 4th as E34/E30. You can note how long the runs was, almost forever.

    I have done quite a lot of different BMWs E46M3s, E24M6 3.5s, E39M5, E30M3, E92M3, E30 spec and all of these cars show exact same 14-14.7.

    Here is a test I did with my own M6 track toy in the back I run 315/35/17 mounted on 12J wheel NT01 tire and always on the back of my minds is wanted to see how much power is this wide tire robbing. 3 runs on 315. stop the car wheel out. Take a second set of throwing starts 255 40 17 same pressure back on the dyno and power shows in 2-3rwhp apart in which I don't know is it coming from the fact that the combustion chamber gets hot, or its intake manifold.

    You mentioned Road test ? Sure I did this as well wanted to find out also on real world what is the difference between 315 and 235 tire width. A buddy with E34M5 3.8 and I did side by side from 20mph at 2nd gear both cars 3.91 210mm. His car and my car at that time were bone stock no cams no stand alone. Test 1) was 235 45 17 25.3" diameter we started at 20mph 2nd gear up to 150mph we were death even side by side not kidding, we did 4-5 times and every time was absolute same. Back to the shop swap tires and back on the same exact spot same speed same all 20mph up to 150mph. With the 315 up to 135mph we were side by side !!! from 135mhp up to 150mph I lost by 1.5 fender, no kidding you. I love testing things on road.

    I was very conservative saying 100hp per liter...but deep down I am sure that the 0.7 More CR will bring food on the table and honestly deep down I am shooting for 215RWHP or ~250- 255BHP SAE crank this will push to about 108-110HP SAE per liter, but time will tell.

    Next week I have to dial upgrade 2 parts on the S38 and its back on the dyno. If I make chilled pass as I call it at 305rwhp and hot passes at 300rwhp then will have clear picture of is it possible to push achieve 110HP per liter from S14 2.3.



    • #17
      Good read, Anri.
      Care to elaborate on your custom cam grind?