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Tii engine dyno results (long)


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I put my recently acquired Tii engine on the dyno this weekend and thought Iwould share the results. The engine came with a recently acquired shell and was represented as needing a rebuild. I adjusted the valves and did all the basic tests and diagnosis before hooking it up and it seemed like it might be an okay engine.

Friday we hooked it up tom the dyno, sprayed a little gas down the intake and amazingly it fired right up after sitting for three plus years! We did some runs and got numbers around 100 HP at 5700 and 100lbft at 4000, a little lower than the original 130 but not bad at all. Unfortunately the HP and torque curves were a little jumpy as was the fuel supply so we went home to return on Saturday to try and tune the injection a little.

Saturday morning we adjusted the valves again Went through the tii tuning manual and checked all injection components and checked the chain tensioner as the chain was a little loose and the motor quieted up nicely. We ended up having to find TDC through spark plug holes as the bell housing we were using had no hole to see the timing BB. Once we got the timing perfectly dialed in we drained the oil for the third time and started doing some more runs.

Ultimatly we got 105 HP at 5900 Rpm and 106 LBFT at 4100, 160+ psi of compression on all four cylinders and 3,6,5,9% on the leak down test (not bad for an engine in need of a rebuild) Anybody know if the original BMW HP numbers are gross HP or real HP?

The engine runs silky smooth and has almost no valve noise, now I'm trying to decide if I want to throw it into the daily driver and pull it when I'm ready to install in the resto shell or hold off for the restoration, what do you guys think?

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Interesting results. What engine dynamometer was used?

Was the alternator/water pump belt connected during this session? Did you get a graph or chart from the dyno operator. I would be interested to see the overall results and not just maximum HP and torque figures.

Can't remember or recall if your tii engine has the plastic or aluminum intake runners.

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Aluminum intake runners and yes the water pump had the belt on, hence the gross HP question. I will upload pictures and video tonight and can send you dyno sheets in a few days if you would like to see them. Another interesting fact is that when I hooded up the stock air cleaner assembly With deceleration valve etc. I lost about 10%. On HP and Torque throughout the runs. The dyno is a super flow sf-901.

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Aluminum intake runners and yes the water pump had the belt on, hence the gross HP question. I will upload pictures and video tonight and can send you dyno sheets in a few days if you would like to see them. Another interesting fact is that when I hooded up the stock air cleaner assembly With deceleration valve etc. I lost about 10%. On HP and Torque throughout the runs. The dyno is a super flow sf-901.

Thanks for the quick responses! Please post your results here so everyone can view. Was the stock 74tii distributor used and if so, did the timing jump around or was it pretty stable for an old engine?

How much did the dyno run cost? Was it on an hourly basis, or per run?

I'd like to see another run after the injectors are cleaned and making sure the KF pump is synchronized to the throttle body (if not already done so).

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Hmm. What were the afr's?

I think the owner's manual has dyno charts iirc.

Cheers,

Ray

Aluminum intake runners and yes the water pump had the belt on, hence the gross HP question. I will upload pictures and video tonight and can send you dyno sheets in a few days if you would like to see them. Another interesting fact is that when I hooded up the stock air cleaner assembly With deceleration valve etc. I lost about 10%. On HP and Torque throughout the runs. The dyno is a super flow sf-901.
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Ray,

Not sure what your acronym afr is, I am a newb on the dyno stuff.

Jgerock,

I will post some of the curve sheets later this week.

Stock 74 distributor was used, and timing was pretty stable. During the days leading up to the runs I establishes that he distributor was good by testing and determining curve was good on a distributor testing machine.The timing was a tad jumpy at some RPM's but all in all was pretty steady on the stock specifications for advance.

I am very fortunate to have a family member who owns the engine dyno shop. I am heavily indebted and will be doing all the maintenance on his 2002 for the foreseeable future as well as cleaning up around the shop as payment. He is a very knowledgable guy who has formula 5000 and Porsche racing in his past and has been dynoing motors for nearly 40 years.

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Yep...DIN standard, not SAE. Speaking in general terms, as I remember it from the time, the DIN standard included the engine accessories and was a more rigid, closer to real life, standard than the gross SAE stripper data.

I know at one time my bone stock '70 tested out at 92 rear wheel HP vs the advertised 110 or so on a chassis dyno using multiple runs. It really blew the mind of the operator as he was used to doing American iron and seeing a huge reduction on the chassis dyno vs advertised HP.

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That's a huge drop 10% with the OEM Tii air cleaner, makes me want to make a change to my 72tii. I seem to recall a post recommending the use of the stock filter as it had some positive effect on output. Apparently that is not true, can't wait to see your follow-up with the video and dyno data.

Divide DIN HP by 1.0139 to find the SAE.

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