205 Mi16 Rr Results

[pee vee 1]

hi all,

out of interest I had my car put on a rolling road today,

 

Spec is as follows

 

totally standard bottom end (1905cc alloy block Mi16) totally rebuilt with new liners.

totally standard head

Shortened QEP (?) inlet manifold

QEP exhaust reangle plate.

 

Standard Bosal 205 exhaust

 

 

Total engine performance mods being...

peterT stage 2 inlet cam

PeterT stage 1 exhaust cam

PeterT Ecu chip for 3 row motronic management

 

 

 

 

it made 164.8 bhp @ 7092 rpm

and 132.1 lbft @ 5636 rpm

 

 

However!!!

 

I REALLY think the standard exhaust is killing the car, as its just not big enough for the engine..

 

but here is where i need your ideas Look at the AFR figures lol

 

 

 

The reason the power is lower than expected.. the car starts to run very rich at the bottom end (around 2k rpm)

 

and rich at the top end! AFR's dropping into the 11s !

 

 

My question is... Should i be looking at the Air flow meter as a cuase of this!? as the fuelling is ok in the mid-range, around 12.6 - 12.8..

 

I do have a spare AFM to try.. but any ideas as to if its gonna be the exhaust restricting the gas out the back, causing it to back up and run rich somehow??

 

 

 

thanks guys..

and to PeterT as his cams clearly make a bit of power difference, even with the fuelling all over the show!

Edited April 19, 2008 by pee vee

[Tom Fenton 1,525]

I think the fuelling is pretty much as you'd want it to be. Max power is achieved at around 12.5-13.0 : 1 AFR, apart from at the very top end where it dips slightly rich to 11.8 it is just as I'd want it to be personally.

[DrSarty 90 1 Cars]

And also, new cams don't necessarily increase top end HP, which is a factor of RPM. They (like mine did) changed the delivery characteristics of the power, and in my case made it more urgent and aggressive. May be worth checking fuel pressure if you think it's important, and old AFMs are notoriously iffy and can need a retrack.

 

Otherwise a good result, if you also bare in mind that IMHO, RR results, i.e. peak figures, usually don't reflect how good a car is on the road/track and so (once again IMHO) are like t1ts on fish.

[pee vee 1]

thanks guys,.

DrSarty, yeah the cams have definitley shifted the power up the rev range a little. and delivery is different to how it was with standard cams.

 

 

Tom Fenton, yeah the fuelling is almost right in the middle in the mid 12s. its just at the top end where it was dropping, which is what i'd like to sort out really. just to get it running right... more concerned with getting it right, rather than the actual figures is produces if im honest!

Edited April 19, 2008 by pee vee

[Stu 18]

Ive got the stage 1 setup on mine, ive yet to run it as ive not long finished putting it back together.

 

I ran the (standard) car on the dyno beforehand though and got 150ish at the flywheel and was a little disappointed to be honest, i had hoped for more.

 

Please forgive me for asking, but arent you a little disappointed with 168bhp with the cams and chip setup buddy?

 

I seem to recall Peter having a dyno printout of a stage 1 equipped Mi with a little more compression doing 170's, i had hoped id be around this figure with mine, but im not so sure now.

 

And yes, i know dyno readouts are not exactly useful for comparison due to calibration etc etc.. but how else can we see if the mods work?

[pee vee 1]

Stu - was perhaps hoping for more.. but as said im not chasing figures.

in my (very limited) experience, engines rarely reach their claimed standard power output, so dont be too disappointed in yours.

 

that coupled with the fact im faily sure the exhaust is restruicing mine,

and it is running a little too rich at the point that it will make figures if its going to.. so im sure there is another 5 or maybe even 10 bhp in there somewhere,

if it was running absolutly spot on.

 

but it was never going to be a road-burning monster with such modest mods!

[whizzer71 0]

I think I would be looking for a little more of an outcome than that (Without being rude) I had a rebuilt Mi in one of my 205's years ago had new liners / pistons ,Hiflow stage 2 head and kent Regrinds 4 branch exhaust manifold with std system and that made around the 180 mark.

I seem to remember reading somewhere that shortening the inlet manifold on these engines robs them of mid range / top end torque ?. (I have a full length inlet manifold If you wanted to try it)

 

I take it you have healthy/balanced compressions on all 4 cylinders ?

 

Just check all the basiscs and work you way forwards

 

Tris

 

Edited April 19, 2008 by whizzer71

[taylorspug 7]

It wont be the exhaust unless you have a fundamental problem with it, Maxi has seen 220hp on his MI running on just a Bosal centre section and uprated back box.

 

Something isnt right with it id say, an MI with any sort of uprated cams should see 170hp at least. My MI with reground cams didnt like having a short inlet on it, the overlap on the cams made the AFM flap flutter really badly, put it back on the std inlet and all was well. May be worth a look?

[taffycrook 2]

I'd forget any thoughts that the std bosal exhaust is holding it back at this level of tune.

I have seen close to 200 bhp on the std bosal exhaust.

The cams could be effecting the AFM, but I have seen good results with both re grinds and inlet only cams on short inlets.

With your set up I would expect 175 plus bhp, could be you need to dial the cams in to get the best out of it.

But don't get too worried about the figures just enjoy it.

Has anyone else run a mi on these rollers to compare the figures.

[petert 550]

I agree that the AFR's are ok. I ALWAYS disregard power at the flywheel and look at the wheel hp. In your case it's making 129hp (or 96kW) which is pretty good in my opinion. I wouldn't expect it to make much more than 135-140 hp at the wheels on a manifold without other mods.

 

Don't you think it's strange that the max. wheel hp was at 6866rpm, whilst max. flywheel was at 7092rpm? How can the two be different? Either way, with the Stage II grind you should have max. hp at approx. 7300-7400hp. As a reference, my Mi16 with a Stage I inlet makes 96kW @ 7100.

 

I'd be verifying the cylinder compression and double checking the cam timing. It's possible the inlet is too advanced.

 

How many km's has it done? Are the rings bedded in properly?

Edited April 20, 2008 by petert

[pee vee 1]

Hi Peter,

it IS on the short inlet still, which is something i would like to change,

 

the engine has done approx 2500 miles i'd say. and i will do a compression check soon as i can!

 

as for the wheel power and the flywheel power being made at different RPM.. yea h I did find that a bit strange too!!

 

will change the inlet when i can, and check the cam timing again, and see what happens!

[James_m 0]

Whats up with the major dips in torque, especially at 4-5k?

Must be quite noticable on the road i assume?

Actually my car with a stage 1 feels like it does the same between 3-4k. Does my head in combined with the utter crap that is the 1.6 box and the stupid rev drop 1st to 2nd!

Edited April 20, 2008 by James_m

[welshpug 1,622]

if the engine is healthy then it has to be down to timing, my std 2.0 has similar dips but nowhere near as extreeme as that, and still pushes 160bhp.

 

Paul the previous owner has had the car on the RR before doing the cambelt and recorded 144bhp IIRC, upon changing the belt he noted that the exhaust cam was severely retarded, every RR session since its produced around 160bhp.

[John_B 11]

It's interesting to see your graph as your engine spec is very similar to mine (1.9Mi alloy block, std rebuilt bottom end, 3 angle valve seats and some very light head work, catcams inlet, std exhaust, no 4 inlet pulley and no 2 exhaust, shortened inlet manifold and reangled ex manifold, K&N filter and magnex exhaust, 2 row ecu)

 

 

I've recently swapped the magnex system for a full bosal and didn't notice any decrease in performance although it hasn't been back on the rollers since. Didn't Maxi have a full bosal on his which was making 185ish?

 

But looking at your graph you have the same dip in torque at 4250rpm as I do. Does this come from the inlet cam (I seem to remember that PeterT's and the catcams inlets are very similar?)? I always assumed that the matching exhaust cam would remove this dip?

[James_R 3]

Does the engine have enough compression?

[pee vee 1]

i'll do a compression check soon i spose but cant see why it wouldnt, its all pretty new.

 

 

Edit. anyone know how much effect having a high presure oil pump would make LOL only kidding..

 

the car does have hi pressure spring and the run was done with the radiator fan on,, but that aint gona make much difference! lol

 

 

Also. PeterT said himself when selling the cams to me, having the inlet only would give it more midrange, but i put both in anyway lol

 

the car was noticably better mid-range before the cams went in... but thats what i expected!!

Edited April 20, 2008 by pee vee

[petert 550]

John_B - which Catcam inlet are you running?

 

Pee Vee - are you running vernier pulleys or standard pulleys? If standard, what combinations?

 

Notice that on wheel hp you aren't that far away from John_B's?

 

If you're running standard injectors and my chip, it shouldn't be that rich at 7000. It should be more like 12.5-12.8:1. This suggests that all is not well and the fuel is there to used but not being burnt effectively.

Edited April 21, 2008 by petert

[maxi 36 1 Cars]

hi all,

out of interest I had my car put on a rolling road today,

 

Spec is as follows

 

totally standard bottom end (1905cc alloy block Mi16) totally rebuilt with new liners.

totally standard head

Shortened QEP (?) inlet manifold

QEP exhaust reangle plate.

 

Standard Bosal 205 exhaust

 

 

Total engine performance mods being...

peterT stage 2 inlet cam

PeterT stage 1 exhaust cam

PeterT Ecu chip for 3 row motronic management

it made 164.8 bhp @ 7092 rpm

and 132.1 lbft @ 5636 rpm

However!!!

 

I REALLY think the standard exhaust is killing the car, as its just not big enough for the engine..

 

but here is where i need your ideas Look at the AFR figures lol

 

The reason the power is lower than expected.. the car starts to run very rich at the bottom end (around 2k rpm)

 

and rich at the top end! AFR's dropping into the 11s !

 

 

My question is... Should i be looking at the Air flow meter as a cuase of this!? as the fuelling is ok in the mid-range, around 12.6 - 12.8..

 

I do have a spare AFM to try.. but any ideas as to if its gonna be the exhaust restricting the gas out the back, causing it to back up and run rich somehow??

thanks guys..

and to PeterT as his cams clearly make a bit of power difference, even with the fuelling all over the show!

 

 

I made 216bhp with a std bosal exhaust. Sorry but its not that holding your car back. Those power figures seem bang on for a std engine. I would ditch that chipped ECU and run a std one. The short inlet will give you a higher peak BHP and I like them coupled with cams, A LOT!

 

3 things I would do before going for another power run:

 

1. Change the ECU for a std 3 row item.

2. Check cam timing.

3. Check compression- although if it was down on compression I wouldnt expect it to have made that much power in the first place.

 

Maxi

Edited April 21, 2008 by maxi

[petert 550]

It won't be the chip Maxi, as it's basically identical to a 355 other than the 7500 limit. Without that he'll never unleash the potential hp. You can see the difference in the attachment - there is none, other than the extended top end. The 161 on the other hand......

[pee vee 1]

PeterT. To be honest i suspect my AFM might of seen better days?

I will check the timing again, but i dont think its out.. its using #4 inlet and #2 exhaust. done to standard timing..

 

the dip in torque does look bad,, but it actually looses 7lb ft over a 1000 rpm range. then immediatly spikes to its highest point (so it dont really loose a lot :s)

on the whole graph..quite a lot of graphs ive seen for mi16s dip just before the 'come on cam' as it were, even the one peter has posted there..

surely it wouldnt make any torque if it didnt have good compression..

 

 

EDIT: i did quickly try the full length inlet last night, but couldnt get the throttle cable to work properly ETC,

so put the short one back on..with new gaskets, and err, im not so sure now that the gaskets were sealing right when it was on the RR. we shall see next time im sure!

Edited April 21, 2008 by pee vee

[John_B 11]

John_B - which Catcam inlet are you running?

 

It's the 4900526 inlet Peter.

[petert 550]

The 526 has slightly less duration but more lift, compared to my Stage II regrind. So I'd expect very similar results between the two engines.

 

Also, the torque scale is very small, with a range of 80-135 lbft, so it's magnifying the dips. Regraph it at 0-210Nm and see what it looks like.

[VisaGTi16v 1]

Have to remember all rolling roads give different results and a standard Mi16 will struggle to hit 155bhp just like the 8v's rarely had much over the low 120's

 

Here is mine when it was done at Sanspeed. Flowed and ported head, Piper 264 fast road cams, k&n and different exhaust, rest standard. It was 142bhp at the wheels. I then plotted it into excel using Dave Bakers method of calculating which bought it out at 168bhp flywheel. Sanspeed themselves calculated it to 166. Weird that yours has a much lower wheel power but nearly the same flywheel but that must be due to the type of rolling road or something. Most important thing is how it drives! You could take it to another place which will report 15bhp more or less! For reference my friends Xsara VTS also at Sanspeed came out at 155 flywheel before they played with the fuel pressure which bought it up to 168 at the flywheel with just a decat and exhaust so sounds about right, low figure to start with was almost certainly him not setting the regulator right.

Edited April 22, 2008 by VisaGTi16v

[John_B 11]

The 526 has slightly less duration but more lift, compared to my Stage II regrind. So I'd expect very similar results between the two engines.

 

Also, the torque scale is very small, with a range of 80-135 lbft, so it's magnifying the dips. Regraph it at 0-210Nm and see what it looks like.

 

Yeah, I can see that if you allow for the scale then pee vee's looks the same as mine. I don't feel that the dip is a problem when you're driving it, I was just wondering what the exhaust cam gives you? Bit more power everywhere or what?

[Jon_Bmw 13]

Sorry to bring an old topic back to light.

 

Pee Vee, where was yours rolling roaded, as I think it maybe the same place as I had mine done on sunday given your location and the machine type.

 

Mine is totally standard, 2 row Ecu'd mi16 with a 2.5" exhaust and a small cone filter. Shortened inlet manifold too. No cams, no chips, nothing.

 

 

 

 

It made pretty much factory power, and the fueling is now at a much more acceptable level. The AFM spring was knocked forwards 4, then back one AFTER the last run to get it to lean out a small amount at the top end.