A TII Question

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Aug 19, 2001 | 03:55 PM

RX7boy

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Joined: Aug 2001

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From: Moscow, Idaho

A TII Question

What made the TII put out more HP in 1989 was an improved exhaust manifold right? Well if you take a pre 89 TII and replace the exhaust manifold with a header wont you get the same effect? Or were there other differences.

Aug 19, 2001 | 04:11 PM

Jef Card

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Well lets see, where to start.

The AirFlow Sensor is a straight through design on the 1989+ verses a flapper door.

87-88 Turbo is smaller and has a twin scroll feature

The IC is bigger on the 89+

89+ sees 1.7 more lbs of boost stock

The Inake manifold porting is a tad bit larger

The exhaust manifold is a bit freer

I believe the exhaust piping is bigger byy like 3/4"

There maybe more but the downside to the 89+ is they weigh like 200-300lbs more than their 87-88 siblings...SO in retro, if you fitted a 89+ block and ECU in a 87, stock for stock the 87 should be faster with the same driver.

Aug 19, 2001 | 04:30 PM

vaughnc

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Joined: Mar 2001

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From: Atlanta, GA

The rotors were lighter/higher compression as well and yes you can put them in a 86-88.

Aug 19, 2001 | 07:07 PM

fc3s.org

Joined: Mar 2001

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From: Charlotte NC

Re: A TII Question

Quote:

Originally posted by RX7boy
What made the TII put out more HP in 1989 was an improved exhaust manifold right?

The 89+ motors had lighter rotors and higher compression. They also had a better turbo, with a more efficient wastegate, better manifold with no twin-scroll. The IC was larger as far as the hot side pipe went, but the core size is the same. I also believe that the intake runners are longer and better designed for more/better airflow.

Quote:

Well if you take a pre 89 TII and replace the exhaust manifold with a header wont you get the same effect? Or were there other differences.

The TII's can't have headers as the turbo feeds from the exhaust manifold. The things listed above, along with more I am sure, are the reasons for the HP differences.