Similar torque and power to my mk1 8v rally car. A lot of people assume that unless you have big numbers bhp the car must be slow. Not the case. I have had a whale of a time with <140hp, getting myself into all sorts of bother.... Well done, and keep using it for what it was put together for.
Racer66, I just checked these dyno results and the readings are for flywheel. These are the type readings you would find on vehicles that were tested at GTI International 2011. Some which are known to me. This is what I would expect and quite good for a 1.8 8v as they test at 105 to 115bhp generally and up to 120lbft @3800ish rpm if working right then drop off like a sone soon after. Your torque value is similar if not better in rabge to a well fettled K-Jet at full pelt based again on some of the vehicles I have tested down here on the same tpye of rolls. So commonising these results you have 1.8 16v type performance + from your modified 8v. No wonder you were able to give competion to Ford Puma's with would run a 1.6 16v Sigma engine though if lightly modified 145PS and 130lbft is possible. Perhaps gearing, weight and your torque profile gave you an advantage! As to the other reading of 160bhp, not sure if that was ever the case in real life.
Not sure what to make of it now then, as the old graph is Deffo wheel figs of 136 I have the calc fly one too. Thus I hoped my second graph from NT-r was atw. I would have expected more from it than the 138 it now seems to be at the fly. SRR are a well known RR and I respect that result. Will have to take it back to srr for a now power run to know where I stand.
Spoke to novatech. Thier figs are calc fly, so Deffo lost lots of power Now to try get it back. 138 for a shrrick cam webber supersprint Ian carvel engine with crissle head seems rubbish power to me.
Well I too operate a dyno dynamics 450DS unit and that result look very good for a 1.8 8v engine.The torque is good and so has been the carb jetting based on those plots. To get to 160bhp at this speed range you need will have to increase torque to near 140lbft and hold it high at say 6000rpm to get that sort of number or hold torque at 120lbft to 7000. Alternatively you can get a misreading and skew the whole number making it no representive. If the car feels the same it has not lost any power, it just read differently on a different machine for unknown reasons. As said agian that type of plot you displayed suggests you lil engine is a very good one. There is an 8v and 16v exercise coming up on the 24th, in which std cars will be tested and compared with factory data. We would be happy for you to come along and get this vehicle tested as you will have std cars to compare to. Contact me if you require more infomation.
Thanks toyotec. I will be at cadwell again with Rafmsa then though. I will put the fly graph on for comment too soon from srr.
Cheers. So lets review what is happening here for this modified 1.8 8v engine. Surrey Rolling Road tested the vehicle previously in April at 165.5bhp@6600rpm and 155lbft@4500 rpm This plots show nothing untoward with ambients. With the bhp scale changed to "wheel power" the result was 136.5hp@6600rpm and 124lbft@4000rpm. So you confirmed by proof, the bhp of the engine vs the whp. OK fast forward so you have an issue where the car drives like crap after replacing an cracked manifold and you take it to Novatec-R who also has a Dyno Dynamics machine. Novatec-R sets the scale to be in BHP, rather than default "HP" or whp. Baseline running rubbish is now 100bhp@???? rpm and XXXlbft@????. The car gets fixed and the new reading is 138bhp@6100rpm and 136lbft@4200rpm ( I back calculated this). The AFR control on the carbs is very good and you did say the cam timing was tweaked. The day was more moist and cooler but ambient pressure was similar to the SRR test. I can confirm the correction in both cases would be at ~ 1.00. It is assumed that an automatic weather station is used in both cases. You drive the car and comment no loss in power. I stand corrected on the Fiestas you were "reeling in" Their are STs = 2.0 I4 Duratec and not 1.6 Sigmas. Duratec motors are no ABF engine and 185-200PS is easy tp achieve with minimal tuning on on a Dyno Dynamics. So to rule out any confusion the car is back to itself. You confirmed that on the race day. One RR is suggesting that the maximum torque is 155lbft and another 136lbft. That is a drop that you will feel in the response and accel of the vehicle. My suggestion is you have a measurement issue at one of the test centres Either way you have very, very, very potent 1.8 8v now, after a tune up, with over 155 lbft from the SRR data or at least 150 lbft from 4300-5500 rpm and because the carbs and the cam timing was fettled probably nearer to 170bhp@6100rpm ( looks a bit tuned ABF to me) Or a still very good 1.8 8v engine capable of achieving 136lbf@4200 rpm which is more torque than a std reference KR car and just about as much power as well. With these things attention to detail is very important as it s quite easy to pull the wrong data from a vehicle subjected to a test and give the wrong impression. Note the S_HP on the Y axis confirms if brake horsepower is measured, where as HP = "horsepower" = whp. Both values are still processed and are not really "raw". Still good lil engine you got there.
Many thanks for the breakdown, I lovew this forum for the technical nature Yep happy with the engine, but still fancy taking it somewhere to see if something more can be pulled out than the current. Just where to go... Will prob whip it down to SRR for a check to see if their is a dyno decrepicancy.
If you think you've lost power, is that being borne out by lap times? Did John M race it at any circuits you've been to, so you could compare times. Obviously there are a lot of other variables, but worth a look. Also, with that sort of power, I'd think you should be in between the 8v and 16v times from Cadwell, in the Mk2 GTI race series. Maybe you could bring it up to Garage Streamline on the 24th for another dyno run and check over from Doktor Toyotek
Then only thing I can see that can be experimented w/o a hardware change with is cam timing and dizzy setting. The fuelling is very good in my IMO. However the dyno information does show a few pulls recorded so this maybe already optimised. If they is more in it it would come from being very anal which would result in not a lot. Maybe the odd 2lbft from low down or 0.5lbft at high rpm. On a dyno you could easily dismiss as "noise". If you are allowed I would suggest stand-alone engine management to have ultimate control on the burn rate of the engine with mapped spark control. That would increase response torque and ultimately the power measured.
Bit tricky to compare cadwell since power change, John did 1:46.2 last yr and I a 1:46.9 this, but I had an open diff this year rather than the LSD. Other rounds I have been quicker iirc.
The prob is toyo, that they did change idle and main jets with these lower figures, could it have ran more hp with the old unknow idle jet and 160 mains. I know they were rich though as plugs fouled. The fueling is sweet now, and like you say not much can change with cam timing, as I see it just changes where the power is, and dizzy maybe run more advance to start but the Mr HC didn't rate doing this? Shame I cannot make the 24th as I said before. Will just sort out the diff in the mean time I think from all this power drama!
I do not really bother about power or its peaks when the torque is present. This you want to maintain at all times. If you car drove well to you on the race day then regardless of what was done it has roughly the same level of torque it always had. You actually drive torque not power. If you did lose say 15lbft or even 10lbft before and after those tests you would be complaining on the race day big time! All engines are different and spark angles to initiate burn and the expansion from combustion can change from engine spec to engine spec. So dizzy settings done both in car for feel and on the dyno can be performed until certain conditions are at MBT or near enough it based in the global nature of the dizzy and its spark advance curve. Dates can be arranged and after the 24th we will have quite a lot of 8v data in to reference from.
If yr doing the lap times then the torque/power spread cant be far off. If it's an 1800 then it's unlikely to have had 155ib/ft of torque... 140-ish is more the norm... high 140 just nugging 150 on bigger spec 1800's. Maybe one rolllers a bit over and one a bit under. Pity yr prob a bit away from us in the Southwest.
I do not know what brand you are basing your reference numbers from but It should not be like that on DD dynos. They are very user friendly machines and I am hard pressed to critique SRR as they are good guys and have a good reputation. If it is a highly tuned 1.8 8v 140lbft would an exception on a Dyno Dynamics dyno for a 1.8 engine, more like 135lbft, which the Novatec-R test suggests. A stocker 1.8 EV can measure from 109-117lbft in good tune, so it puts this racing engine in perspective. We do not know which one is closer to the true measurement of the vehicle based on spec. I am convinced that this is a process problem with measurement.
Im talking about competition spec engines here Eddie, and figures off an engine dyno not run down guestimates. A good fast road spec engine is certainly more like 135 ib/ft as you say...some a bit better, particularly bigger capacity 1900/2ltr engines. Decent comp spec 8v's don't make masses of extra torque, but they hang on a lot longer.
In the beginning the question that I had asked was to establish if different rolls where used which as ruled out as the a casue for the delta in power that this thread is name after. Fortunately the baselines and the work that has been carried out in this specific case have been performed on a specific brand of machine that estimates modelled flywheel power or processed whp so any other test done on bench or other brand chassis rolls is irrelevant and just adds unwanted noise to the specific problem. I am not doubting your references mind, just not the type on numbers I would expect on this type of chassis rolls. So bear with me on this. Also I am backed up by various data from different test places and instances such as Paul in his 2.1 16v high comp thing that achieved 155lbft at inters, Hotgolf in his 2.1 carb monster with 155lbft and F2 Stu in his 150lbft screamer, Ben S at various DD locations with 160lbft (briefly) in his Plenum'd MS 'd ABF. All on the same type of rolls at different locations that are repeatable and in larger engines. And I have quite a few data plots now that can be added to the mix that show similar trends with maximum achieved torque. Not only that, there is also data to show real life G-Force as a correlation check. So 1.8 8v with 155lbft at such low relative engine speed is a questionable measurement. However the parties that have generated both sets of data I am sure will not deliberatly tamper with machine settings to cause such an error. However I still think this delta in measured torque before and after needs to be understood for a car that actually runs the same between tests. This is an issue with measurement rather than an issue with vehicle as I do not think this car is down "30bhp" what so ever.
Mr HC, where in the SW are you? I do head that way as I have fmaily in North Cornwall and Exeter... Alex
Out of interest, I have the post rebuild Sun dyno chart also from PMR. I will scan this later and get it up too
