ITS vs ITR

[EkstenRacing]

Is the e36 325 2.5 liter a better fit in ITS or ITR these days. I've heard the intake restrictor they're forced to run in ITS really boggs them down. I've also heard that that it's hard for them compete in ITR with the larger displacement cars.

[snk328is]

I would check the race results for the regions you're interested in racing with. From what I understand the East Coast and Mid Atlantic are the places to be for racing Bimmers in ITS/ITR. My general impression is that most are running ITR, but that's just seat of the pants feedback.

Here in Cen-Div, ITS/ITR is pretty dead.

[Andy Bettencourt]

The E36 325 is the absolute best choice IMHO. It is weighted very well for its power output potential. A 210whp E36 has the potential to win every ITR race with the rest of the stuff right.

What larger displacement cars are you talking about?

[benspeed]

Go with Porsche! 3.0 four cylinder. Tough to find a donor car that's not $10K - torque beats the bimmers and hp is similar. The weight sucks at 3055 lbs - no mercy from the CRB when I begged for a diet....

The smart money 325 E36 for ITR but why be a lemming?

[Z3_GoCar]

The E36 325 is the absolute best choice IMHO. It is weighted very well for its power output potential. A 210whp E36 has the potential to win every ITR race with the rest of the stuff right.

What larger displacement cars are you talking about?

I know someone who dyno'ed their Stickley motor (M-50) with Kromkraft headers, 190hp on a DynoPak. That's the same hp as my 2.8 when it had a M-50 manifold on it instead of the M-52 top end killer that's on it now. There's no way to get 210 at the wheels unless someone also swaps for the S-52 cams too :018:

[Andy Bettencourt]

I know someone who dyno'ed their Stickley motor (M-50) with Kromkraft headers, 190hp on a DynoPak. That's the same hp as my 2.8 when it had a M-50 manifold on it instead of the M-52 top end killer that's on it now. There's no way to get 210 at the wheels unless someone also swaps for the S-52 cams too :018:

I'm not going to race dyno's with you but that number stinks. I have heard that there is a ton to gain with advanced ECU work.

We have 323's up here that make more than that.

[benspeed]

Yep our 323 boys are ferocious - easily laying down 210 or more. Top quality cars with some advanced ECU development. 100% legit. Damn drivers are tops too. :-)

[Ron Earp]

I'm not going to race dyno's with you but that number stinks. I have heard that there is a ton to gain with advanced ECU work.

We have 323's up here that make more than that.

I think that CA IT competition is a bit different than NE and SE competition. With the large fields on the East Coast a lot of development happens that doesn't happen elsewhere.

[lateapex911]

I know someone who dyno'ed their Stickley motor (M-50) with Kromkraft headers, 190hp on a DynoPak. That's the same hp as my 2.8 when it had a M-50 manifold on it instead of the M-52 top end killer that's on it now. There's no way to get 210 at the wheels unless someone also swaps for the S-52 cams too :018:

The dyno work I've seen was during the ITACs investigation back in the pre restrictor day. An average, no build, chipped and headered E36 put down well over 195 on a Clayton dyno. The (many and multiple) sources told me that was a loooow number compared to what the big boys were doing at the time. Conservative reports were over 210 at the wheels. Guys like Whittle had years of development and much more. And, IIRC they got through the tech shed at the ARRCs, where the intake/heads were off, and the main stuff was checked.
(Now, they could, of course, have been running a set of light pistons, rods, etc etc, as the engine didn't come all the way down, but.....)

[Ron Earp]

Conservative reports were over 210 at the wheels. Guys like Whittle had years of development and much more. And, IIRC they got through the tech shed at the ARRCs, where the intake/heads were off, and the main stuff was checked.
(Now, they could, of course, have been running a set of light pistons, rods, etc etc, as the engine didn't come all the way down, but.....)

Yep, and you can go search on this board, and others, and find numbers published by those teams before all the hoopla hit about their weights being wrong in ITS.

And then, of course, there were some BMW's that were a bit more BMW than they were supposed to be. BMWs packing up and going home for the weekend when a cylinder head was displayed at tech registration on Friday night, tales of 325s that were 2.8L when the car changed hands, and so on.

[GKR_17]

. And, IIRC they got through the tech shed at the ARRCs, where the intake/heads were off, and the main stuff was checked.
(Now, they could, of course, have been running a set of light pistons, rods, etc etc, as the engine didn't come all the way down, but.....)

As I recall, tech was getting lax in those years. They were not pulling heads at that time.

210 in a 323? Sounds like ITR numbers to me. Not pointing fingers, but it is incredibly naive to say a car is 100% legit if it has never been checked.

[benspeed]

No - 210 is a "S" number - you gotta get out and see the top equipment...even the top ITS Rx7s are putting down 185-190 nowadays with better ECU development.

[Andy Bettencourt]

As I recall, tech was getting lax in those years. They were not pulling heads at that time.

210 in a 323? Sounds like ITR numbers to me. Not pointing fingers, but it is incredibly naive to say a car is 100% legit if it has never been checked.

I have NOT seen any dyno sheets on the 323's. Our guys up here build great stuff and have been running them for more than a few years. I think Irish Mike built one if anyone has info on that but these 323's WALKED our S2000 at the Glen up through the Esses. At the time, S2000 at 3005 and 200whp. 323's at 3000lbs in ITS trim.

I think as ECU advancement keeps moving, anything with variable cam timing has a bright future.

[GKR_17]

Using the published ITAC expected power gains, a full build ITR E46 328 should have around 251hp at the crank. Using a 15% power loss, that works out to 213hp at the wheels. Using the same logic, the E46 323 should be putting down around 188 at the wheels. A few better maybe, but 22? If that's true we should revisit the BMW power multipliers, or take a few engines apart.

[Andy Bettencourt]

Using the published ITAC expected power gains, a full build ITR E46 328 should have around 251hp at the crank. Using a 15% power loss, that works out to 213hp at the wheels. Using the same logic, the E46 323 should be putting down around 188 at the wheels. A few better maybe, but 22? If that's true we should revisit the BMW power multipliers, or take a few engines apart.

I bet you aren't using the right numbers.

Run the 323 and 328 with a 30% multiplier.

[GKR_17]

I bet you aren't using the right numbers.

Run the 323 and 328 with a 30% multiplier.

E46 328: 193hp x 1.3 = 250.9 drop that 15% to get 213.3 at the wheels.

E46 323: 170hp x 1.3 = 221.0 drop that 15% to get 187.9 at the wheels.

[lawtonglenn]

perhaps the BMWs lose less than the average 15% in the drivetrain?

here is a link from a guy who was surprised to find only 10% loss in his stock E46 M3:

http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/11736-drive-train-power-loss.html

and another showing actual graphs of only 10% loss

http://www.rri.se/popup/performancegraphs.php?ChartsID=768

I know that the E46 M3 is not and E46 323, but even if there is only a 10% drivetrain
loss then to get to 210whp the multiplier would have to be:

170hp + 37% = 233 - 10% = 210

interesting :rolleyes:

[GKR_17]

perhaps the BMWs lose less than the average 15% in the drivetrain?

here is a link from a guy who was surprised to find only 10% loss in his stock E46 M3:


Could be an optimistic dyno, but I believe the real culprit is that BMW understates the stock numbers. I've heard that it might be because of insurance rates in Europe. No one complains when they get more power than stated, for the other case just ask Mazda...

Either way the 30% gain the ITAC uses takes that into account, and was back-calculated from whp numbers using the 15% loss assumption.

Assuming 15% driveline loss, a 323 at 210whp is making 145% of the published stock power.

[Andy Bettencourt]

And BMW's typically outperform the multiplier. The E36 in ITS was never weighted with the process, 30% was used in ITR...and 30% was applied as the standard for the rest of the I-6 Bimmers. It may be we are finding out that is a conservative number but I haven't seen any sheets to date on the 323.

[JeffYoung]

Irish Mike's E46 is an ITR car I think, right?

Ben you've seen ITS RX7 sheets at 190 at the wheels? Have a hard time believing that one.....

[GKR_17]

Mike's was a 323, but he converted it to a 328 under the VIN rule, sometime in 2008 as I recall.

[lateapex911]

Curious as to why? Did he want to change classes? or did he feel it had a better chance with the other engine? (As in, the 328 motor is a better race motor, for either more performance potential, or more robust)

[dj10]

Mike's was a 323, but he converted it to a 328 under the VIN rule, sometime in 2008 as I recall.

The Irsh Mike's 328 was FAST @ last years ARRC until he kissed a piston, from what I heard. DNS

[GKR_17]

Curious as to why? Did he want to change classes? or did he feel it had a better chance with the other engine? (As in, the 328 motor is a better race motor, for either more performance potential, or more robust)

If you could run a faster class for basically the same cost wouldn't you? I'm pretty sure Mike likes to run at the front of any field he's in. Need to be in ITR to get that done in the SE.

I had thought the 328 was much more competitive in class. The E46 323 was classed durring the E36 witch hunt and is 75 to 100 lbs higher than it would be per the process if it were classed today. Power claims of 210whp certainly put that logic into question, or then again maybe they are actually 328's...