more V8 horsepower
Discussion
Done some more work on the V8S .. tidied up the trumpet base blending where it'd got the casting edges in and couldn't get a decent radius, all smooth now .. played with the advance weights too and then needed to sort the fuelling so adjusted the regulator something close .. graph to follw 
but the numbers are good hehe
edited to add .. for those owners looking at shorter induction pipes, this is with a very shortest pipe I could get between plenum and air flow meter, and nothing the other side of the meter .. I'm going to do a comparison versus a very long pipe to see what differences there are.
>> Edited by trackcar on Saturday 11th February 11:54
but the numbers are good hehe edited to add .. for those owners looking at shorter induction pipes, this is with a very shortest pipe I could get between plenum and air flow meter, and nothing the other side of the meter .. I'm going to do a comparison versus a very long pipe to see what differences there are.
>> Edited by trackcar on Saturday 11th February 11:54
Hi peter, well to be honest I didn't believe the figures when I first tested the S on the new dyno, so i booked into Nobles the very next day and it made with 3bhp or something of what I'd run it at on mine so I'm confident the results are *there or thereabouts* right.
Then being the natural sceptic I am I ran it again and again and again and although 244 was the highest, the lowest was still 239bhp so in all I've gained 100bhp over teh first fuel-starved version of the car.
Power now is right up there with Pies and V8Smiths cars which are remapped but relatively standard spec, mine has the induction tweaks and now the changed ignition advance curve which is obviously tipping the balance up towards the younger cars, ie offsetting the natural losses of a 107k miler! lol. It's running about 34deg right at the top end now (difficult to tell cos my cheap timing light seems to waver a bit) so that's helping keep the power up top. before it was pinking at anything like 28deg. The previous hp was on 95 ron and this is on optimax though so that will account for a little bit of the gain also by being able to advance the timing more than had been possible before.
On the air flow meter there was no bellmouth at all, just took the pipe off the end of the meter. I'll go try a longer intake pipe now and report back the findings ..
joo
Then being the natural sceptic I am I ran it again and again and again and although 244 was the highest, the lowest was still 239bhp so in all I've gained 100bhp over teh first fuel-starved version of the car.
Power now is right up there with Pies and V8Smiths cars which are remapped but relatively standard spec, mine has the induction tweaks and now the changed ignition advance curve which is obviously tipping the balance up towards the younger cars, ie offsetting the natural losses of a 107k miler! lol. It's running about 34deg right at the top end now (difficult to tell cos my cheap timing light seems to waver a bit) so that's helping keep the power up top. before it was pinking at anything like 28deg. The previous hp was on 95 ron and this is on optimax though so that will account for a little bit of the gain also by being able to advance the timing more than had been possible before.
On the air flow meter there was no bellmouth at all, just took the pipe off the end of the meter. I'll go try a longer intake pipe now and report back the findings ..
joo
ok not quite the result i was expecting .. 243.3hp and identical midrange too .. with an old convoluted tube from a chimaera. Seems that at up to 240hp at least there's apparently (on the basis of this simple back to back test) no induction length change gains upstream of the airflow meter, though of course short pipes keep heat soak into the pipe to a minimum which would be important if routed next to the exhaust.
As you know, I ran a setup which had plenum->AFM->filter all directly connected in line with each other, with the filter in a cold air box fed from the back of the bonnet. I don't know how much of the power gain was directly attributable to the length change (rather than getting cold air) but it seemed to me that the throttle response was crisper. I don't think this was just an inertial effect, but maybe just an indication that the air flow into the hotwire sensor was better behaved being immediately downstream of the filter rather than the wrong end of six feet's worth of boundary layer plus a sharp corner?
>> Edited by greenv8s on Saturday 11th February 13:41
>> Edited by greenv8s on Saturday 11th February 13:41
pies said:
Great improvement Joolz,whats the current run of the air intake pipe as i know this makes a fair bit of difference
Currently it runs from the plenum to a very short straight pipe, maybe 4 inches long then to the airflow meter, then there's an immediate 90 degree bend to the filter which rests just behind the nearside inner wheel arch.
trackcar said:
Currently it runs from the plenum to a very short straight pipe, maybe 4 inches long then to the airflow meter, then there's an immediate 90 degree bend to the filter which rests just behind the nearside inner wheel arch.
Sounds familiar
, found this to be the best all round positon on the V8S, effectively putting the filter behind the NS headlight in the wheel arch liner, which is in itself makes a nice air box (which I also have a feed from the front grill to it). Like you I have a very short 4" silicon between the plenum and AFM, being short it can take the weight of the AFM without having to bolt it down, so it stays directly in line. Only slight issue can be the AFM can get very hot as its almost directoy above the NS manifold, I have mine protected with a large insulation blanket (foil backed stuff). By taking weight off the dizzy weights its allowed you to delay and avoid too much advance at peak torque reaping the benefits further up the rev range ala 3D ignition
. As you are playing on your own RR joolz, do me a favour in that configuration do back to back runs with the AFM gauze on and off. I've run mine in both configuration and feel that its seem to run stronger without, it might just be me. See if you can spot any differnce on the RR, not just peak figures but across the board as I think peak may stay pretty much the same. Oh to have a RR in the garage
. greenv8s said:
I haven't done back-to-back tests myself, but a very experienced RV8 specialist advised me against taking the mesg off. Apparently it has a significant effect on the large scale turbulence which makes the hotwire more predictable/consistent.
Yes I heard that too, it stabilises the air flow so that the AFM can get a more stable and accurate reading(measurement) of the air mass. However, if the car is happy to run without it, which some are, it removes an effect 10% addtional restriction to air flow. Mine is happy without it and seat of pants it seems stronger, also measuring air flow output to the ECU with a voltmeter on the move it gets it to peak out (5V) earlier in the rev range on mine too. Just think it would be intersting if Joolz did a back to back on his as he has the new toy
. His car may not like it removed, but if its happy and it gains a bit then job done .
trackcar said:
Power now is right up there with Pies and V8Smiths cars which are remapped but relatively standard spec, mine has the induction tweaks and now the changed ignition advance curve which is obviously tipping the balance up towards the younger cars, ie offsetting the natural losses of a 107k miler! lol. joo
Excellent gains there Joo, you must be very pleased after getting those shock results last year and I am led to believe you were quick around the track before, they better watch out now....
nice one the car is nearly twice as powerful as before Yeah Pies car is standard spec.... isnt it Harry
Mine isnt strictly speaking standard spec either, the heads have been ported by TVR power, a 218 CAM, the inlet manifolds are the larger 500 ones and are also ported with the larger flared trumpet base, ACT reworked Y piece, smaller bore ACT manifolds then of course the Tornado remap. I dont know what difference each mod makes as I have never done before and after sessions although I know Harry and Pies did with the exhaust and flared trumpets etc and they got small gains for each. Im always interested to know of ways to improve induction as mine breathes very well now and Im looking to change the pipe from the fluted one to a smooth silicon pipe like Pies. Interesting that the shorter pipe didnt ake any difference.
Good gains keep them coming
Mike
V8Smith said:
Power now is right up there with Pies and V8Smiths cars which are remapped but relatively standard spec, mine has the induction tweaks and now the changed ignition advance curve which is obviously tipping the balance up towards the younger cars, ie offsetting the natural losses of a 107k miler! lol. joo
Yeah Pies car is standard spec.... isnt it Harry
Mike
its pretty standard only a Y piece, set of trumpets bit of fiddling on the air intake and a remap pies said:
Power now is right up there with Pies and V8Smiths cars which are remapped but relatively standard spec, mine has the induction tweaks and now the changed ignition advance curve which is obviously tipping the balance up towards the younger cars, ie offsetting the natural losses of a 107k miler! lol. joo
Yeah Pies car is standard spec.... isnt it Harry
Mike
So its standard then
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