On the Rollers

[Mik]

Thought I'd comment on my old baby...

Simon,

Hmmm......suggestion.....I think it could be the APR exhaust thats restricting the flow. High backpressure can sometimes give you more torque but less highend power due to flow restrictions..... I would try a Miltek dual or something to see if that makes a difference......

I had a new exhaust made for the beemer which increased to 3.5" no cats.....almost gave me another 100bhp as I could wind up the boost...without melting the exhaust. Now running over 700bhp on 95 oct

Expect Jeffs car to be just around the 400 mark.....

Mik

Jeff I bought the car just after it had been on the rollers so wasnt really sure if the owner was pleased with the results or not. However its hard enough to use the power the car has now so I am not sure I would want much more to be honest and the torque is awesome. That said I have seen cars with a lower spec (i.e Dougs) make 400bhp which to me doesnt make much sense as my car has no faults on VAG-COM and passed through a MRC healthcheck.

The car does however have an issue with the electrics as the voltmeter normally reads only just over 12v even after a decent run. I think this is due to a faulty voltage regulator which needs to be sorted at some point. Could running low voltage cause a power drop due to weaker spark?

I'm going to be devastated if I only get an improvement of 11BHP after RS4 ICs, fuel pump, injectors and MRC remap.....I got 365 on the same RR without the extras

[si_hill]

Hi Mik, nice to hear from you.

To be honest I am not really after any more power at the minute, more interested in sorting out the handling and fitting the recaros sat in my garage.

I was however intrigued by cars with very similar spec's that were getting quite alot more power. If it is the APR exhaust and I could gain another 50bhp from a dual then it might be worth changing. Surely though with no cats as it is currently running backpressure shouldnt be that high?

Will have to have a word with the MRC guru's at some point and see what they reckon.

Glad to hear the beemer is going well

Thought I'd comment on my old baby...

Simon,

Hmmm......suggestion.....I think it could be the APR exhaust thats restricting the flow. High backpressure can sometimes give you more torque but less highend power due to flow restrictions..... I would try a Miltek dual or something to see if that makes a difference......

I had a new exhaust made for the beemer which increased to 3.5" no cats.....almost gave me another 100bhp as I could wind up the boost...without melting the exhaust. Now running over 700bhp on 95 oct

Expect Jeffs car to be just around the 400 mark.....

Mik

Jeff I bought the car just after it had been on the rollers so wasnt really sure if the owner was pleased with the results or not. However its hard enough to use the power the car has now so I am not sure I would want much more to be honest and the torque is awesome. That said I have seen cars with a lower spec (i.e Dougs) make 400bhp which to me doesnt make much sense as my car has no faults on VAG-COM and passed through a MRC healthcheck.

The car does however have an issue with the electrics as the voltmeter normally reads only just over 12v even after a decent run. I think this is due to a faulty voltage regulator which needs to be sorted at some point. Could running low voltage cause a power drop due to weaker spark?

I'm going to be devastated if I only get an improvement of 11BHP after RS4 ICs, fuel pump, injectors and MRC remap.....I got 365 on the same RR without the extras

[ChrisS2]

The car does however have an issue with the electrics as the voltmeter normally reads only just over 12v even after a decent run. I think this is due to a faulty voltage regulator which needs to be sorted at some point. Could running low voltage cause a power drop due to weaker spark?

The voltmeter on my S2 is the same and i have been wondering if low voltage is the cause, or one of, for my mis-fire at high boost. I'd check the voltage at the battery and see if it tallys up with the voltmeter, mine is out by around 1v.

Cheers,

[si_hill]

Chris - I have checked the voltage at the battery and it pretty much tallys with the gauge. However also tested the alternators output at the battery and that seems to stay pretty constant even under load which to me points to the regulator being screwed. Unfortunatley on the S4 you cant get to the alternator to test the output at source so it could possibly be a problem in the loom.

I suppose the question I need answering is, would running low voltage (approx 12v ish) effect power??

[ChrisS2]

Possibly, i had the same problem or a simular problem with my Golf, the alternator wasn't putting enough volts out to the ecu causing the accelerator not to work, car ran but accelerator didn't work. I'm not sure what voltage the ecu needs to power the coil packs on the S4.

[ChrisS2]

Right, ignition coil supply voltage should be ok with 12v, but it is a little on the low side tho. Getting the regulator changed could only help.

Cheers,

[ZeroK66]

376BHP - that is lower than I thought it was. What is the fats time in MIKS car? PM me mate - lets get together, I am free this weekend. Have a run in eachothers cars, see how they compare.

Cheers,

[GrahamS4]

Itching for Jeff's results now!!

[jeffw]

302.3BHP 315ft/lb at the wheels....

[s4woody]

i no them cos i went there..mine ran with only 1 failing lambda 298.5 at the engine and 233.6 at the wheels..once i get my lambda,s replaced i,ll go back and get it rechecked..
although i did show 385.5lb of torque which is summit near 522.7 of Nm's..so im not that dissapointed..
it ran 311bhp at the crank on QST's dyno last year but only showed 198bhp at the wheels..even though its sick its still feels quick..looking at the print out its making 309.2lb of torque at the wheels which is about 419.2 Nm..

[Mik]

Dont know if you will get another 50, hard to say....you also have stock manifolds which have tiny ports (again good for torque). I know the APR looks and sounds the part.....thats why I got it, but its still small-ish, think only 2 and a bit inched so in combination with the manifolds it will give you decent backpressure

Symptoms like....plenty of boost and timing but no power.....whilst the exhaust turns blue

I know a guy with RS4 engined S4 and he was struggling to get power with the same version APR....also decat.

Just my 2 pence....

Mik


Gald yu like it, I know I did.....there is always more things you can change. If you look at Zeros car, hes got big manifolds and and FMIC.....those make a huge difference IMHO.

Hi Mik, nice to hear from you.

To be honest I am not really after any more power at the minute, more interested in sorting out the handling and fitting the recaros sat in my garage.

I was however intrigued by cars with very similar spec's that were getting quite alot more power. If it is the APR exhaust and I could gain another 50bhp from a dual then it might be worth changing. Surely though with no cats as it is currently running backpressure shouldnt be that high?

Will have to have a word with the MRC guru's at some point and see what they reckon.

Glad to hear the beemer is going well

Thought I'd comment on my old baby...

Simon,

Hmmm......suggestion.....I think it could be the APR exhaust thats restricting the flow. High backpressure can sometimes give you more torque but less highend power due to flow restrictions..... I would try a Miltek dual or something to see if that makes a difference......

I had a new exhaust made for the beemer which increased to 3.5" no cats.....almost gave me another 100bhp as I could wind up the boost...without melting the exhaust. Now running over 700bhp on 95 oct

Expect Jeffs car to be just around the 400 mark.....

Mik

Jeff I bought the car just after it had been on the rollers so wasnt really sure if the owner was pleased with the results or not. However its hard enough to use the power the car has now so I am not sure I would want much more to be honest and the torque is awesome. That said I have seen cars with a lower spec (i.e Dougs) make 400bhp which to me doesnt make much sense as my car has no faults on VAG-COM and passed through a MRC healthcheck.

The car does however have an issue with the electrics as the voltmeter normally reads only just over 12v even after a decent run. I think this is due to a faulty voltage regulator which needs to be sorted at some point. Could running low voltage cause a power drop due to weaker spark?

[GrahamS4]

302.3BHP 315ft/lb at the wheels....

Really?

My money is on 302.4BHP @ the wheels

No you have to be winding me up!?

Come on stop the joke, what did ou get?

[s4woody]

graham thats bang on..i saw it with my own eyes..all both of them..

[GrahamS4]

Oh, I thought it odd I was having my leg pulled, but couldn't believe I was so close!

Frankly, I want a prize for that! Bang on the beans in whole numbers and only 1 tenth out otherwise.

If I had come to that conclusion by any technical know how I it could be a useful skill, sadly I did not.

Hmm, I think Jeff was hoping for more. Mind what's that, about 375-380ish BHP realistic flywheel figures?...respectable. Hopefully Jeff either has his prior figures at the wheels or got an estimated flyhweel figure from the dyno for the purpose of comparing with his last result.

Is it usual with modifying the S4 engine with K04's to see the torque figure rise a lot less than power? Jeff has siginificantly more BHP than my car (52BHP at the wheels), but only 15ft/lb more torque (at wheel figures).

I'd love to see the plots Jeff if you can get them posted.

Was a fun day had by all? Any more stories/results?

@Woody - Shame your car was not 100% health, but none he less positive results. I think QST have a MAHA dyno - mixing and matching flywheel/wheel HP figures from different dyno types will lead to brain frazzling!

[s4woody]

yeah QST have a maha dyno..they recorded a loss of 113bhp which i felt was alot ..but atleast with the few mods i have done (no main-cats and RS4 Y pipe) i have seen an increase in torque from my QST dyno run..oh and lets not forget my bonnet slot..although the bonnet was open today..