Compression test results
#1
Compression test results
I did a compression test on my 00 today and got the following 200,196,200,202 on a warm engine. From online reading these seem to be nice consistent numbers. I was concerned about my virtual dyno numbers of 140/124. I'm thinking I need to ditch my RL header for an RB and possibly my Monster flow intake for a coldside set-up.
#6
Some good info on intake diameters/lengths.
[NA] 135whp with stock NA8 long block - MX-5 Miata Forum
[NA] 135whp with stock NA8 long block - MX-5 Miata Forum
#7
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Why?
The dyno chart you have posted is excellent for what, based on your signature, I assume to be a mostly stock 2000 engine with a few bolt-ons.
For what it's worth, I would not expect a significant improvement from replacing the riceland exhaust manifold with a racingbeat unit. The materials quality will be a bit better, but there's not a significant difference between the two in terms of design.
The dyno chart you have posted is excellent for what, based on your signature, I assume to be a mostly stock 2000 engine with a few bolt-ons.
For what it's worth, I would not expect a significant improvement from replacing the riceland exhaust manifold with a racingbeat unit. The materials quality will be a bit better, but there's not a significant difference between the two in terms of design.
#8
Emilio from 949 racing typically quotes about 155-160 for a healthy 01+ block with a fresh 99/00 head with the bolt-on's I have . I was thinking with a .5 less compression I would see maybe 145-150. Since my shortblock seems ok, I may invest in a set of cams from somewhere. Any Idea's or input is appreciated. I know this is "Turbo Miata" but this site is much more tech. oriented than m.net.
#10
I have tuned the timing tables. I'm running roughly 33-34 degree's total timing under WOT in the upper rpm's. I have also played with AFR's between @ 12.4 -13.4 on the chance my AEM wideband was off. The AFR changes netted me nothing really +- 1-2 whp, while more timing just set my knock sensor off. The spike around 5500 corresponds to a drop in map readings that I think is from an intake resonance. I have adjusted my target AFR in that region to try to counter the spike.
Last edited by 6speed; 10-28-2013 at 04:46 AM.
#12
All dyno's will vary all the time. Stressing over anything sub-5hp is a waste of time IMO.
That said, I've so far had great luck with VD with over 5 runs all showing within 1-2hp of each other.
IF that plot of yours is accurate, that's pretty impressive for what it is.
I have a mint 01 engine with a 3" midpipe and e85 that I made 122/117 with repeatedly, your 140/124 sounds about right for the mods. I run little bit less timing though, just because 10:1
*edit: kinda curious about your spark map: why run 30* in the cruise cells and 33 at wot? Also why are your maps scaled to 240kpa? Planning for boost soon?
That said, I've so far had great luck with VD with over 5 runs all showing within 1-2hp of each other.
IF that plot of yours is accurate, that's pretty impressive for what it is.
I have a mint 01 engine with a 3" midpipe and e85 that I made 122/117 with repeatedly, your 140/124 sounds about right for the mods. I run little bit less timing though, just because 10:1
*edit: kinda curious about your spark map: why run 30* in the cruise cells and 33 at wot? Also why are your maps scaled to 240kpa? Planning for boost soon?
#16
Not my quote, perhaps someone elses. Consult the FSM for compression numbers. USDM NB2 should be around 205psi when new, broken in and warm. Leakdown under 2% for new motors. Most used NB's we see are in the 140-170psi range. They'll still run OK but make less power. Most compression loss from normal wear is from exhaust valve seats. Often times a <100k motor with medium compression can get most of it back with just a valve job.
Sorry for jumping in the thread out of nowhere. As you were.
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#18
?
Not my quote, perhaps someone elses. Consult the FSM for compression numbers. USDM NB2 should be around 205psi when new, broken in and warm. Leakdown under 2% for new motors. Most used NB's we see are in the 140-170psi range. They'll still run OK but make less power. Most compression loss from normal wear is from exhaust valve seats. Often times a <100k motor with medium compression can get most of it back with just a valve job.
Sorry for jumping in the thread out of nowhere. As you were.
Not my quote, perhaps someone elses. Consult the FSM for compression numbers. USDM NB2 should be around 205psi when new, broken in and warm. Leakdown under 2% for new motors. Most used NB's we see are in the 140-170psi range. They'll still run OK but make less power. Most compression loss from normal wear is from exhaust valve seats. Often times a <100k motor with medium compression can get most of it back with just a valve job.
Sorry for jumping in the thread out of nowhere. As you were.