Which is faster?

[Aptyp]

another thing that isn't brought up is rod angle. I's are capable of smooth reving because the rod angle is so minimal.

[nando]

well sorta.. look at any BMW M motor. the S54 for example has a pretty extreme rod ratio - 1.50:1 which compares with the eta's 1.60:1. It's not really going to affect how smoothly it revs, but it will affect cylinder filling efficiency (weighted towards better low end filling). the S54 gets around it by using vanos to improve filling in the top end (in addition to having an excellent head, intake and exhaust system). In fact BMW may have done that on purpose in order to achieve the goal of a flat torque curve.

[csab327i]

whats the difference between the i/e rod
and also super eta pistons/325i pistons

which set up is the best with eta crank when wanting a n/a engine?

[BMWkid91]

With The I head its has stronger valve springs this is much different to the softer E head. this will give it a higher RPM range and HP becuse the E bottom end has a longer pistion Stroke given the name "Stroker". If you want more performance upgrade the PCM to i and chip it along with cold air and exaust so she can breath better, becuse your engine is a glorified air pump.The only down side to this if it has an E cluter you would have to change the Tachometer out "simple". With my gusses you probly would be able to push aproxemently 200 Hp or more

[nando]

lol

[SpecM]

lol

yes, I did too

[Holland]

Also in for the LOL.

[rcfanatic]

Anyone (nando?) have a dyno from a stock eta? I want to compare published hp and whp

[digger]

Anyone (nando?) have a dyno from a stock eta? I want to compare published hp and whp

half the problem with comparing stock dyno numbers to quoted manufacturer crank numbers is the stock dyno numbers are probably high mileage engines with questionable maintenance history and this leads to BS % losses from crank to wheels and therefore bogus estimated crank hp claims from those who run their cars on the dyno.

[nando]

Anyone (nando?) have a dyno from a stock eta? I want to compare published hp and whp

I have one but it's not very good, they only took it up to 4k.



in addition to digger's comments there is a fundamental problem with comparing plots from different machines. At best you can get a feel for the shape of the curves and a general idea of a high-low range, but you really can't compare it with the stock quoted figures.

[rcfanatic]

Thanks guys

[rcfanatic]

So comparing the stock eta to the 885 swapped eta (with max 125hp).. it looks like the 885 *hurts* torque on average about 20lb-ft (up to 4000rpm). The peak torque is also 18 less than stock. So this is due mainly to the CR? Since Mitch's swap with the milled head and 9:1 ratio brought the max torque up to the same as stock, and also occured at about 4000rpm. Did the plain 885 swap have any i components?

[nando]

I think the ones I posted were entire "i" swaps - intakes, electronics, wiring, etc.

[eta]

Well my M20B27 with 885 head, 325i intake manifold 082 AFM and mortonic 1.3 qith a chip that did not fuel properly and an eta TB made 125 whp (160 fhp apparantly)@5250 rpm and 145 ft.lb (~186ftq apparantly) torque @3900 rpm. I get 125 wtq (~165 flywheel ft.lb apparantly) torque at 2000 rpm. Given I live in the U.K my motor starts of with a higher CR so the final CR of the engine is 9.35:1. I have kept the stock eta exhaust/manifold.

With the 325i TB and AFM adjustment it came alive with more torque across the rev range. Yet to get it dynoed agai though.

CR would seem to make the difference.

[I got it, yes!!]

Damn, now I need to get my combo dynoed. m20b27 bottom end, 731 head with 325i cam and valve springs, 325i intake and TB. E electronics with custom mark d chip made for this combo.