C
chris
Guest
Any ideas why we sometimes get flat spots even when everything is sound with the engine and ignition system? any possible cures?
Currently reading:
Why flat spots at 3-4K revs?
A
Alan
Guest
i find mine just doesn't pick up until around 4
R
rsmallwo
Guest
floor it and see
If you start from a stand still down a long straight road.
Floor it in first and you will get pulled into the back of your seat and through all the gears the range at which you get some G's will increase due to increased speed and changing gears. But doing it this way means when you change gear you will already be 3500rpm in next gear which is the start of the torquey range.
If you just cruising about and then floor it but are below 3000rpm you won't get alot of umff at all, not until the revs start to climb
I have a 1.8hlx 98s mk1 (but i have air con n a sunroof....bizarre but true!)
If you start from a stand still down a long straight road.
Floor it in first and you will get pulled into the back of your seat and through all the gears the range at which you get some G's will increase due to increased speed and changing gears. But doing it this way means when you change gear you will already be 3500rpm in next gear which is the start of the torquey range.
If you just cruising about and then floor it but are below 3000rpm you won't get alot of umff at all, not until the revs start to climb
I have a 1.8hlx 98s mk1 (but i have air con n a sunroof....bizarre but true!)
T
Tom
Guest
Re: floor it and see
Partly engine design, partly noise regulations. Cars are tested at half their max RPM (ie 3000) so they are tweaked down a little so they make less noise.
Partly engine design, partly noise regulations. Cars are tested at half their max RPM (ie 3000) so they are tweaked down a little so they make less noise.
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Tom
Guest
Re: Re: Re: floor it and see
Which engine?
Which engine?
OP
OP
chris
Guest
Re: Re: floor it and see
makes the car very **** if i want to overtake when im at 3,000 revs in second
.
Remapping the ECU any use or just changing the fueling?
makes the car very **** if i want to overtake when im at 3,000 revs in second
.Remapping the ECU any use or just changing the fueling?
Y
YoGiS
Guest
Re: Re: Re: Re: floor it and see
Remapping will not help a great deal in low RPMs...
I think the truth about these engines is they have to be driven above 4000 RPM and trashed to get a good effect out of them
Remapping will not help a great deal in low RPMs...
I think the truth about these engines is they have to be driven above 4000 RPM and trashed to get a good effect out of them
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christian
Guest
Re: Re: Re: Re: floor it and see
honda d16a6 again.
not bothered about adding extra power low down...
If the car had as much power at 3,500 revs as it did at 2,500 then i would be happy.
honda d16a6 again.
not bothered about adding extra power low down...
If the car had as much power at 3,500 revs as it did at 2,500 then i would be happy.
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Tom
Guest
Re: Re: Re: Re: Re: floor it and see
Its a 16 valve engine, they never have very good low power.
Get a diesel or an 8v engine.
Its a 16 valve engine, they never have very good low power.
Get a diesel or an 8v engine.
L
Lew B
Guest
Re: Re: Re: Re: Re: Re: floor it and see
You could try a fast road cam. I have got to admit I didnt like trying to overtake in my Bravo. Piper may take on the Job of sorting the cams. Give me a shout and I can see.
Cheers Lew B
You could try a fast road cam. I have got to admit I didnt like trying to overtake in my Bravo. Piper may take on the Job of sorting the cams. Give me a shout and I can see.
Cheers Lew B
S
Syed Taq
Guest
Re: Re: Re: Re: Re: Re: Re: floor it and see
Check your spark plug, air-filter and fuel-filter.
Thanks,
Check your spark plug, air-filter and fuel-filter.
Thanks,
T
Tom
Guest
Re: Re: Re: Re: Re: Re: Re: floor it and see
Lew, a fast road cam will move peak power and peak torque UP the rev range. It will make it worse.
Lew, a fast road cam will move peak power and peak torque UP the rev range. It will make it worse.
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Ian
Guest
Re: Re: Re: Re: Re: Re: Re: Re: floor it and see
So what's the point in fast road cams really? or are they a pure waste of time?
So what's the point in fast road cams really? or are they a pure waste of time?
OP
OP
chris
Guest
Re: Re: Re: Re: Re: Re: Re: floor it and see
mines a rover! the car is very quick as long as i dont get it stuck in the flatspot.
decatting helped a little.
Just ordered a 4-2-1 manifold rather than a 4-1 manifold as i think this may help?
mines a rover! the car is very quick as long as i dont get it stuck in the flatspot.
decatting helped a little.
Just ordered a 4-2-1 manifold rather than a 4-1 manifold as i think this may help?
T
Tom
Guest
Re: Re: Re: Re: Re: Re: Re: Re: Re: floor it and see
A fast road cam like all hotter cams gives you more top end power and a bit more on the usable rev range.
It won't give you more low down power or more low torque. A slow road cam will do that but then you loose top end power.
If you look at the before and after graphs for Yogis' 1.8, the power and torque are pretty much the same until you get to just over 4k at which point the fast road cams just take off.
If you go for faster road cams or race cams then you will loose maybe 15-20% low end power and torque. Basically the hotter the cam the more peakey the engine becomes and the less low end you have.
A fast road cam like all hotter cams gives you more top end power and a bit more on the usable rev range.
It won't give you more low down power or more low torque. A slow road cam will do that but then you loose top end power.
If you look at the before and after graphs for Yogis' 1.8, the power and torque are pretty much the same until you get to just over 4k at which point the fast road cams just take off.
If you go for faster road cams or race cams then you will loose maybe 15-20% low end power and torque. Basically the hotter the cam the more peakey the engine becomes and the less low end you have.
A
Anonymous
Guest
Re: Re: Re: Re: Re: Re: Re: Re: floor it and see
ok i now want a fast cam, and a free flowing manifold too. Whats the score with these on a mkI HGT?
ok i now want a fast cam, and a free flowing manifold too. Whats the score with these on a mkI HGT?
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Tom
Guest
Re: Re: Re: Re: Re: Re: Re: Re: Re: floor it and see
About £1500
About £1500
B
Big Andy
Guest
Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: floor it and see
Mine also has this characteristic, it helps if you switch off the aircon but they are still there. No help I know but at least your not alone!
Mine also has this characteristic, it helps if you switch off the aircon but they are still there. No help I know but at least your not alone!
OP
OP
chris
Guest
Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: floor it and see
Depends where you shop. I have realised now that virtually everything can be found cheap.
Just got a stainless manifold honda engine for £100 delivered.
think cams might be more difficult to find cheap.
Depends where you shop. I have realised now that virtually everything can be found cheap.
Just got a stainless manifold honda engine for £100 delivered.
think cams might be more difficult to find cheap.