For a 2nd gen 87 N/A with StreetPort

front

6.5, 7, 6.7

Rear

same

This was done on a mazda checker at 250rpm's. The graph on back says 6 is average or still good.

What do you guys get on the "certified mazda checker" Please no other readings from different pieces.

The car made less power then my Stock port 89GXL. This one has an intake and straight pipe exaust and a decent A/F ratio. The difference between the two is my extensive intake porting/matching exc done on the old GXL. I'm thinking there was a napkin stuck in the intke or something.

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in kPa 6.5-7 would be OK... for a turbo.... its low for an N/A.... N/A's have higher compression... I think thats you're problem... Is it a new rebuild???

 

89-91's compress better than 86-88... like 9.7:1 vs i think 8.7:1... but a difference anyway...

 

Well the mazda checker had a graph in the back and said 6 was bar level at 250rpm's. The engine has only 7,000 miles on iit's Atkins rebuild and 3mm seals. I think if the seals are 1 or 2 piece then mabye this will have to do with the suppsedly lower compression at cranking speed but regardless I think its fine. The mechanics said thats normal. And yes its a S4.

Does anyone else have numbers from this checker?

 

Ya S4 had lower compression rotors which is good for high boost