Campeck

I just realized i put the 2.7L headers on my 2.5L motor during the swap.
anyone know if they are different sized runners? Ide hate to be running around with my new motor with sub par performance.

Campeck

event hough it does feel faster than the old motor. and i have a dyno from this engine. 127rwhp. i suppose i could dyno it again.

haha...watch the 2.7L headers be like the best power maker on a 2.5L motor.

testarossa_td

Can't wait to find out....

Chupa

Pretty sure there's no difference. The only differences on the '89 2.7 were ... the crankshaft to get it to 2.7 and the anti-roll bars from the previous turbo. Besides, the hp on the 2.7 didn't really change, but the torque went up accodingly ... made it more driveable IMO. Either way, timing of the exhaust pulses shouldn't have ever changed unless they were trying change the torque curve (usually at higher rpms), but they didn't.

jgporsche

the displacement was not from a crank..... it was bore size

tod84944

The head for a 2.7 will not work on a 2.5, so I would suspect the headers are different also.

Campeck

dang. the intake valves and ports are DEFINATLY larger then the 2.5
the 2.7 exhaust valves are only like half a mm bigger than the 2.5...so are the exhaust ports anydifferent?

does anyone have the head of both or the manifolds?

but yeah. 2.7L crank is same as 2.5L crank. it has the S2 block pretty much.

xsboost90

i hope the crank isnt different, then i'll have to take the 924s crank out of my 2.7.....Bore size went up and power went from 155 to 163....I believe the header is the same though.....

Techno Duck

I have a '89 engine next to me right now, the exhaust port on the head is roughly 1.5 inches.

I know the major difference in the intake ports is that the ports are ovaled on the 2.7L head where they are round on the regular 2.5L head.