Car down on power since rebuild?


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Aerodeckb18

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Basically rebuilt the b18c in my car recently, as the b18c4 bottom end previously was away burning lots of oil etc. Now when rebuilt I used oversized pistons which when only rebuilt the car had issues with flat spots down low. I have since replaced the p30 standard ecu with a chipped one using the h-tune baseman while I save to have it mapped by Vtec6000 off here. But last night when driving it it feels a lot slower than before so I took a video on the same stretch of road as I had taken one previously and the difference is massive. I don't know if it's because it's only done 1000 miles since being built but it seems the old c4 bottom end and jdm head combination with a bog standard p30 was a lot quicker, which cannot be right. Any help would be great!
 
That's perfectly normal. Usually after rebuilds they use mild settings to run in the engine until the final tune in. Don't expect to be making power on something close to a basemap.
 
pateras_vtec said:
That's perfectly normal. Usually after rebuilds they use mild settings to run in the engine until the final tune in. Don't expect to be making power on something close to a basemap.
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So do you think that the htune have used a detuned map? I wasn't expecting proper power but was worried by the power decrease, That puts my mind at ease mate thanks!
 
Bearing in mind that they didn't tune the car I just bought the p30 from them with what they called a b18c6 road tuned map?? I thought it wouldn't have made it a lot slower?
 
You looking for power to soon in the break in period if you ask me.

Plus just because your bored it out does not mean you have more fuel going in, or flowing more air, both make power, over bore will only allow more room for air and fuel-- if adjustable . So if you are on a base map of one or the other, you need to get a programmable ECM to be able to map your setup correctly.

you might also want to get a better flowing head. And if you do that, you better have a great flowing header and exhaust system in place. Prior to that get a CAI...the list goes on and on...

Good Ruck!
 
Glad to hear its not just got slower then!! Im sure Vtec6000 will have it running and mapped correctly was just worried about the mean time.
 
Every engine has their own personality. What works for mine might not work well with yours. The map that will be done on your car will deliver an entirely different result from the htune one. Usually all companies in maps like this they give out ultra safe maps with lower ignition timing etc.
 
You are going to love it when it is properly mapped.
 
@ Tama 666 LOL,exactly what I wanted to hear!!Its really doing my head in ATM just seems to be so sluggish and I keep thinking a million things are wrong with it, But hopefully a good tune will have it pulling hard again!!
 
This is the problem with "basemaps" they can be miles off. Do a quick compression test on it to see if compression is close to even across all cylinders. I would just drive it easy till you bring it down for mapping.
 
not to worry mate, i was running a base map on my b20 when i got ecu from h-tune, felt down on power as well, once i got it mapped there was nearly 30bhp difference from base map.
 
And what if compression is off? Yeah mate I've been driving it real easy since.
Sambo cheers mate hopefully mine is the same!
 
If the compression is "off" on the cylinders or you have inconsistent readings across the 4 then it tells you somethin aint right!
 
Compression test will tell you about the state of the engine mechanically, not about the map (though that may have caused the engine trouble).
 
Its bareley broken in and a/fr's on base map are probably overley rich to elimate or reduce detonation and without the correct ign timing you will lose power which is prob your issue. Do a comp check on it for peace of mind and map the screamer...
I recentley rebuild my itr head which included relapping the valves and once built before firing up i did a comp test on it and cyl 4, 2 and 1 were equal (190ish) and cyl 3 was on 125 but once started and run for a few miles and i did another test they all equaled out, so give things that contact each other some time to 'get to know each other',, rings amd cylinders in your case and valves and seats in my case..
 
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