Tii Performance

[Keith02]

Proud owner of a 74 Tii.

What is generally acknowledged as the " most bang for your buck " performance upgrades for the stock injected motors ?

[kris]

Proud owner of a 74 Tii.

What is generally acknowledged as the " most bang for your buck " performance upgrades for the stock injected motors ?

A step header and appropriate exhaust would be on my list. After that, you go straight to internal mods...cam, porting, custom pistons, valves, custom tuned k-fish etc. etc. Just please don't remove the stock airbox

[Guest]

Do nothing. IF you want to faster, buy a different car.

[jrhone]

Do nothing. IF you want to faster, buy a different car.

Kinda agree...aside from tuning and maybe exhaust....because of the value of the car in stock form I'd leave it alone....buy a carb'd 02 for modding....just my opinion.

[c.d.iesel]

Factory Spec adjustments of the entire motor - nothing more

[gwb72tii]

Do nothing. IF you want to faster, buy a different car.

go mod a non-tii, easier to do and cheaper

plus tii's are getting rare

get the kfish properly adjusted and

get a suspension kit/sway bars and sticky tires and a driving instructor

[JerryC]

Maybe an OD five-speed and 3.90 diff, and get a dyno tune from someone who really knows tiis. Have the distributor tested and curved if necessary. Take some excess weight out of the car, but in such a way that you can put it back.

Just my .02 worth.

[ingraham]

Invest your money in BMW CCA driver training -- car control clinic, high performance driving school, autocross. You will go faster and safer, and the skill will apply in anything you drive.

[TobyB]

Heh- yeah, make sure your dizzy's up to snuff an' buy a Pertronix.

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[Arshloch]

just improve in general , in period correct fashion and spirit.

[peteinjp]

The reason everyone is responding this way is because the tii system cannot compensate for any changes that require a different fuel curve. Fuel delivery cannot be "tuned." That said I went with a 4.11 rear end and a 5 speed. I had a supersprint header and went back to the stock manifold. However many have run relatively mild cams with reportedly good results in terms of higher end power albeit at the cost of having lost the "perfect" tune in other rpm ranges. Honestly the tii well tuned is a great balance for the car if the suspension, tires and brakes are well sorted. Originality aside its hard to improve on the engine and still use the tii hardware.

The 4.11 lsd gearing really puts the power down well and I don't see the highway much so for me its a win win.

The ignition is the best area to work on. Pertronics or some other points eliminating system is a good thing. The timing is very important on the tii. Be sure you have the stock dizzy and its running the right curve.

[jgerry2002]

There are ways to improve the fueling if you are modified.. but it will take you awhile to figure out what the motor needs (unless maybe you tune cars for a living).

I agree with all the posts, if your distributor has not been touched in 50-100k then rebuild it, your car will thank you. Also rebuild every last part of the linkage in the injection system. This will also make a huge difference.

In my car, I have metric 2.2L, mild cam, higher compression, '02 again header, IE exhaust.

I ended up sending my injection away and getting Wes Ingram's "sport" linkage earlier this summer.

Its probably the most cost effective (not perfect by any means) way to increase fuel delivery to the motor.

Basically it works by interacting with the warmup circuit to introduce more fuel at 1/2 to 3/4 throttle based on how it is set up.

Basically with the flow of my motor, the stock fuel curve is ok up until about 3000rpm. Once its starts to go beyond this, I've found that my pump can not really keep up with the necessary fueling.

With the linkage in place, I've found my air/fuel ratio (yes I have a wideband.. which is necessary) has improved. I am at least down in the 13s vs the 15 (!) I started with on a full throttle 2nd gear pass...

[ray_]

I'll echo what the others had said...

I was initially going to post something similar to what Pete said: you might go with a 3.90 diff with the 4sp or a 4.10 with the 5sp. This will affect highway cruising a bit, tho.

Otherwise make sure the stock systems are performing properly, and maybe go to Pertronix.

GL,

Ray

[JsnPpp]

Just preaching to the choir here but I'd stick with making sure everything is spot on to spec before adding new pieces. It's a good thing to do regardless and then when/if you decide to add some "go fast" parts you will really have a feel for what improvements have been made.

I'm all for originality, but a Pertronix made the single biggest difference in drivability/starting/smoothness than any other change on both my Tii's. It or something like it is highly recommended.

-Jason

[Keith02]

Thanks for all the input.

The car is , and will remain, stock in appearance. I maybe give the Petronix a try.