Delanoso's 2.9L Build

[e30sh]

Did they mention anything about the machine work required to fit the 84 mm crank? Any chance they had an ETA crank lying around?

[digger]

What kind of torque #'s should a 2.9 make at lower RPM's?

160ish rwtq is the ball park where id want it to be on a fairly mild 2.9L build for the street. The camshaft and exhaust can really reduce that big time though if you arent careful

[digger]

I'm not sure really. My understanding is that they measure everything before the put it together. Some of the parts were from a kit, some of the parts were bought separately. I know they used separate M52 135mm rods because of the shape and he says they were weighed and measured for balance. You'd think in that process they'd measure the crankshaft as well. His thought is that a forged shaft in a kit designated for the block/head combination might go unnoticed because it was part of a kit where an M20 cast crank would stand out. Still seems kind of unlikely to me unless the actual tech who built it didn't put 2+2 together on 2.9L = 84mm crank.

That's a fantastic way to do it myself. Aaaaand now I feel dumb. I'll do that tonight.

the pistons would be way down the hole (almost 5 mm) and it'd be obvious. plus a typical 75 mm stroke m20 doesnt normally make 150 tq at 2500 rpm its normally like 130 if its lucky.

[e30sh]

What kind of torque #'s should a 2.9 make at lower RPM's?

[ForcedFirebird]

I see you are using Ross pistons. Was the stock 885 crown shape used?

[ForcedFirebird]

I see you are using Ross pistons. Was the stock 885 crown shape used?

[Delanoso]

doubt its a 75 mm crank in there....anyway you said the shop built the engine how would they not know what crank is in there......

I'm not sure really. My understanding is that they measure everything before the put it together. Some of the parts were from a kit, some of the parts were bought separately. I know they used separate M52 135mm rods because of the shape and he says they were weighed and measured for balance. You'd think in that process they'd measure the crankshaft as well. His thought is that a forged shaft in a kit designated for the block/head combination might go unnoticed because it was part of a kit where an M20 cast crank would stand out. Still seems kind of unlikely to me unless the actual tech who built it didn't put 2+2 together on 2.9L = 84mm crank.

Pull a plug, find TDC, and stick a socket extension in there. Mark it at TDC, and then rotate the motor. Easy way to measure stroke in just a few minutes.

That's a fantastic way to do it myself. Aaaaand now I feel dumb. I'll do that tonight.

[AWDBOB]

Pull a plug, find TDC, and stick a socket extension in there. Mark it at TDC, and then rotate the motor. Easy way to measure stroke in just a few minutes.

[digger]

doubt its a 75 mm crank in there....anyway you said the shop built the engine how would they not know what crank is in there......

[Delanoso]

Turns out the guy who tuned my ecu is no longer with the dyno shop, which makes me even more suspicious that he slapped a tune in there with out ever putting the car on the dyno. My shop is concerned that there's a forged M52B25 crank in there instead of the B28. He's also concerned that cam timing has been retarded by decking but at least we have an adjustable cam gear to correct that. We'll likely get it in the shop next week to pull the covers and oil pans to see if we can measure or see casting numbers. First thing though, he wants to try swapping out the AFM just in case that's causing the power loss as well as the idle issues. I feel like we've been through three of them already though so I don't have much confidence in that.

[2mAn]

Id aim for a realistic number around 175-180whp and anything more is a bonus. Might need more cam, but should be a strong setup as-is when properly tuned

[Delanoso]

Sucks that the numbers are low, but I think you have a lot of potential in that motor once the tune gets sorted out

Appreciate the vote of confidence. We'll get it sorted out eventually.

[Delanoso]

To "jump" from map to map, you would have to be playing with the WOT switch, not just going up/down a hill, the AFM will show load.

That is the idea I was missing. As simple as that seems. No worries about those pictures. I've been cruising the Alternative Tuning threads and thought I saw something I understood. I completely get that I'm a noob, which is why I want to hire you to help me get the MS tune straight. I just want to understand enough that I follow some of the what's and whys.

Seems like sensors are good, now it's likely down to internals or tuning. Heading over to the shop this afternoon to develop a course of action. There's a remote chance it's not the 2.9L I think I have. I don't want to crack it back open but he said he'd do it if it became necessary.

[2mAn]

Sucks that the numbers are low, but I think you have a lot of potential in that motor once the tune gets sorted out

[ForcedFirebird]

It's not the 8°, it's the ability for the ECU to "catch" what's going on. 8° can be the difference between going fast, and fighting detonation.To "jump" from map to map, you would have to be playing with the WOT switch, not just going up/down a hill, the AFM will show load.

There's a lot of math going on in an ECU. The main timing table is just one part, and sorry if it's confusing, but that pic was just to show what happens if the TPS is bad. There's other multipliers in the grand scheme of things. The CTS, IAT etc all have an effect on final values in a running engine (that table gets "multiplied" by other tables to make adjustments).

OK, so the TPS checks out. .025" should be fine, the stock ECU is actually more tolerant to air gap than MS will be. I want to say from memory, it's supposed to be .039" (1mm). 526hom is a little on the light side, but is in tolerance (+/-10%, or +/-54ohm).

hmmm...