rolling road results of a tweaked S4...a realistic expectation

[dodge1979]

Today saw my S4 on the rolling road at Northampton Motorsports...what a day. After Saturdays pre visit visit I was prepared for what happens! Ive been concerned about the fuel pressure for a while having fitted an adjustable regulator..so was keen to get it set properly throughout the rev range... That was my main aim for today, along with the power runs to see how the various mods and tweaks actually perform in a real enviroment...so to de-myth the hype over mods and improvements I hope you guys will read and take onboard the post I write with understanding..particularly in the view that not all that is thought is correct in terms of tuning and power gains. I must clarify that my whole aim for the rebuild of my esprit was to make more efficient the systems that the esprit uses...chargecooler, injection, ecu and exhaust. I wasnt interested in chasing big numbers, just smoothing out what is already a fantastic car, regardless of its restrictive systems etc..making the best of what we have..much like my thread on the delco braking system...getting it working to its best efficiency! Ill be giving a detailed rundown of what went on today hopefully along with some pics/data when I can upload them.

There is a lot of what I would refer to as myth surrounding improving these cars, myth, unfounded claims and hopefulness are things to be clarified. I hope its of interest!

[Bibs]

There is a lot of what I would refer to as myth surrounding improving these cars, myth, unfounded claims and hopefulness are things to be clarified. I hope its of interest!

Eg?

[cjtpb13]

Darren looking towards more on this...

[karmavore]

The problem is the inconsistency in dyno's, their configurations, and their operators. It makes it very difficult to compare numbers.

Other issues contributing to the "myths" you speak of may be Marcus's XX HP chips (meaninglessness numbers) and the small sample size of SE/S4/S4s that have posted dyno charts.

I'd expect raw HP measured at the wheels to be 230-265hp on a non/mildly modified S4, assuming everything is in working order.

Good luck.

[CHANGES]

Hi Luke,

I think your expectations for non and mildly modified WHP is not that far out the upper figure could be pushed up a bit depending on loses and if the fly wheel power went over the 300bhp mark. But as many are finding it is not that easy to do.

On the other point you made about dyno's.... All I am going to say on this point is,if you use a top quality dyno with a qualified technician, backed by top engineers, Then consistency and accuracy is a given...

This argument on dyno's is coming from bad information by disgruntled punters who's expectations exceed their cars performance.

In this particular case Darren has had his Esprit done on the same dyno as mine and the Sport 300 I recently restored. The S300 engine was rebuilt to factory spec. The dyno results which can be seen in the restoration section were ...... surprise surprise....the same as the factory figures for bhp and torque... I rest my case..

What Darren will share with you all is the Mod's he has done and the tuning issues it created. Then the first dyno results followed by the final results after his mod's were synchronised with the standard ECU.

It should open your eyes to how mod's can send you down in power until set up properly on a dyno.

With Ref. to power figures quoted on after market chips....I agree not worth the ink...However when incorporated with mod's and set up on a proper calibrated dyno operated by a qualified technician...then gains can be made... with limitations...

Please don't turn Darrens thread into another dyno argument the same as the 412 thread . if anyone wants to rant on about Dyno's

start a fresh thread purely on that subject....Thankyou.

Dave

Edited June 21, 2012 by CHANGES

[dodge1979]

Thanks for the valid points there luke and dave...as mentioned, I originally built my esprit with the view to making it more efficient..im not a number chaser, but I am realistic in what I believe cwn be improved upon. Firstly ill run through the mods ive made, in terms of the engine itself. First off is the well known ram air mod, coupled together with a k&n filter.then as the air passes through the standard s4 turbo(new) its then cooled by the.standard chargecooler unit but using an electric bosch pump and a custom built radiator in replacement of the standard unit. Mine is physically as big as cqn be fitted in the front of the car. Next the cooled air passes into the plenum, dump valve fitted between chargecooler and plenum nozzle, and into the.completely stock engine. No mods, porting or matching off faces/gaskets has been done. Fuel is supplied via larger injectors both primary and secondary. Pressure is controlled by an adjustable regulator in replacement of the.standard unit on the fuel rail, fuel is supplied using an uprated pump. The intake charge is ignited using standard grade original spark plugs set at factory recomended gap.

Next, the exhaust gasses pass through the standard cast manifold, through the turbine, through a sports cat and out a free flow exhaust. All sensors are standard original.equipment, the ecu being the gm unit using a standard s4s chip, not.the.s4 chip. Cam timing is.original not 104/104 as some others run.

This setup combines the widely regarded upgrades used by many qnd are all bolt on items.

Youll.have to bear with me as I write in sections folks!

As.mentioned, the rolling road at Northampton is a highly regarded setup throughout motorsport here in the uk. Its been used on two other esprits recently, one being the s300 built to factory spec which produced factory figures upon its dyno runs. My initial run up after warm up.showed a disappointing 265bhp. Which, for a 17year old car is.good and spot on original factory s4 power, however due to the mods mentioned i.did.expect to.see more. But this in a way was a good thing as it shows that simply bolting on items does not give instant power. My torque and.bhp graphs were shaky and full of.peaks and.dips throughout the rev range. My lamba readings were off the scale running rich, which I was aware of anyhow. So the first issue to look at was the overfuelling issue. This, however, turned into a fairly serious fault concearning the.secondary injectors. Basically, over time one has unseated itself and as such began to leak.fuel under pressure. This meant the plenum nozzle needed to be removed which showed the retaining plate for the secondary injectors was out of.shape enabling them to.move under extreme pressure..this was rectified and another power run was made. This showed a favorable gain of about 8bhp and a reduction in the over rich fuelling, enabling the lamba to come down to a readable scale. The next move was to adjust the pressure regulator to bring the fuelling down to a more correct adjustment.

Whilst these adjustments were being made and tried, we had noticed what sounded to be a leak of.boost pressure on power runs...so the dump valve was removed and a blanking plug fitted to see if a weak spring in the bov was the cause. However, there was still an.audible leak of boost pressure but we had gained 2bhp! So the next step was to check all induction hoses, clamps and gaskets using a soapy solution. This instantly revealed a host of leaks from the.plenum gaskets (which were new), and the two red hoses attached to the turbo to chargecooler and cooler to plenum nozzle. It was found that one securing clip was fractionally loose, and the rest were secure but still allowing a fraction of.pressure out. All were tightened as much as possible and another power run made.

This resulted in a hike of.about 20bhp to bring the power up to.292bhp! A fantastic result, but more importantly the curves on the graphs for.torque and power became very smooth with no peaks or dips at all. This showing that throughout the rev range the engine was performing very well indeed. Final checks were made on the dump valve which resulted in it showing up to.have a weak spring and as such was leaking a fraction of boost. Enough to loose 4bhp. Final.adjustments were made to the fuel pressure and the final result was a.smooth, very well balanced power curve showing a true 292bhp.

Now, in addition to the work carried out yesterday, it has highlighted a few issues that I am sure other owners would.not.be aware of. The use of different injectors requires the fuelling pressure to be adjusted to suit, the fact that even with new gaskets and hose.clips.its still possible to leak boost and that a dump valve could be weak and.you would never know. All these simple things can only be highlighted and.corrected with the use of a.dyno to achieve maximum benefit from any changes away from standard spec...with regards to my own car, my next steps are to replace all.hose.clamps with a higher quality item, change the red hoses to new ones, and using a gasket sealant like wellseal seal all gaskets on the plenum and use it on the hoses as well to make.double sure.that they are perfectly sealed. Furthermore a new.dump valve will be purchased as im running the smaller turbo there is a real.chance of stalling it if driven hard.

On the actual road, the car may well make another 2-3bhp again, due to the.ram air mod comming into function and the chargecooler would run slightly cooler from circulating air in the engine bay. These two things unfortunately dont happen on the rolling road and as such cant be tested. I do believe though that from the work carried.out this shows the realistic results of all the commonly approved mods made to our cars and how they can function correctly together to.give a better driving experience....or they can hinder the cars performance without you actually knowing it

Ps ill post the graphs up tonight I hope!

[hopo]

Very interesting reading... Your certainly not messing about!

[dodge1979]

Ha ha thanks for that! Yes no messing around here! Now ive finished work for the day Ive got a bit more time to sit down and look at the data printouts I have from yesterday. Unfortunately I dont have all of them yet, Ill recieve a file containing them soon. I have a select before and after comparison..although the final 292bhp chart isnt amongst them, the 288bhp run beforehand with the faulty dumpvalve still connected is. As I mentioned, it was discovered to be leaking a tiny amount under boost and costing a couple of horses...

Its interesting to see what is actually happening throughout the rev range as a brakedown is included. The standard S4 has a max bhp of 264 at 6500rpm and a max torque of 261 at 3900rpm. Now as we know its easy to get caught up with chasing maximum figures and a lot of people like to see bhp bhp bhp....well the real truth and benefit of these mods can be seen throughout the rev range in the data...

With the setup Im running, im reaching peak bhp earlier on at 5758rpm whilst the torque at 3900rpm is 268 rising to 281 at 5200rpm. This clearly shows an excellent gain in mid to high range power and torque, reaching factory levels earlier in the rev range..

Also, as can be seen when I post the graphs, the curve on the power and torque is progressive and smooth throughout the range. Its these points that I believe a fair number of people will not realise is where your genuinly seeing the benefit and how it changes the way the engine runs.

[arbell9]

What does attesting session at the dyno cost??

[dodge1979]

dyno3.pdf

Alex, Im sure prices will vary from company to company, but at Northampton its based upon an hourly rate. In this instance it was £90 per hour plus VAT, but whether the rates vary depending upon the level you want to go to I dont know..

Just to explain, on the first graph the red lines show the first run, as explained all over the place! The black lines are the much improved figures...

[sailorbob]

Some Q's:

How was the MAP measured?

Was standing start overboost used?

Did you take a datalog during the run?

[karmavore]

Please don't turn Darrens thread into another dyno argument the same as the 412 thread . if anyone wants to rant on about Dyno's

start a fresh thread purely on that subject....Thankyou.

I wasn't trying to. Sincerely. I was merely sharing my thoughts on the issues Darren posed with regard to the "myths" and "unfounded claims". I'm glad you both have found a dyno that tells you what you want to hear. :-)

[dodge1979]

Well, Im not an expert in Dyno's and in honesty probably not the best person to ask about them..this thread is more so for the results achieved on them. So Derek, I can only give a simple answer Im afraid without asking the technical people themselves. In terms of MAP, I know that they attached a takeoff to the system and their sensors read far beyond the capabilities of the unit fitted to our cars..With regards to a standing start overboost...as far as I was aware the correct method for achieving power runs is in fourth gear only...which wouldnt allow a standing start power run? Maybe Ive misunderstood your question though. With regards to datalogging, I didnt take one if your refering to an espritmon type log. It would have been a nice comparison or an additional set of data...however Im having no luck with the program on my laptop if Im honest. Basically the laptop is poop and the usb ports seem to have their on and off days. Poor excuse but its the truth!

If Ive not answered these correctly or misunderstood Ill try for a better answer...this is my first experience on a dyno so Im learning here aswell!

Luke luke! No I agree with your comments earlier...I think claims of super plug in chips and wow yove got 400bhp are rubbish. At best their an engine destroyer. A true way to tune and improve is not to wack up the boost, throw more fuel down the ports and say wow. Everything in the system needs to be finely tuned to work in harmony with everything else...an engine is a fine balancing act to get it working wonderfully. What I meant by myths was this regarding the chips, but also some claims that for example, exhausts will give you extra 20bhp (for example, not neccassarily an actual claim)...Yes Im still running a CAT, albeit a freeflow sports unit, so that is a restricition in the system, but reduced considerably over the standard unit. The point is that these items only come in to true effect when balanced in conjunction with other items...its not a simple case of listing the possible bhp gains, adding them up and thats your total...unfortunately its still a belief that thats the case with some folk ( particularly in the badly bodykitted youngster fraternity!)

It is, unfortunately, a sore area for a lot of people. A lot of money and time is spent on these cars and sometimes the hype is far greater than the results, but you need to keep an open mind on these things. To expect big numbers for big spend doesnt equate. It can cost a hell of a lot for only a few bhp...but who would want to spend £500 to £1000, say, to only gain 5-8bhp? As an example..but if you thought you would be getting 20-30bhp youd be feeling better about yourself....and if the car feels quicker, then it must be right...right? In honesty, how many people have spent their hard earned cash, done some improvements, noticed a difference in the way the car performs and has left it at that...Im sure most have. The unfortunate truth is that they may not be getting the full benefit of that upgrade because its not neccassarily working in union with other parts of the system. This they wont know because they wont need to spend £300 on a few hours of dyno time to tell them that the expected 40bhp increase they should be getting is correct. Or so they think.

So, I did unfortunately preempt this to be a bit of a risky thread as previous dips into dyno talk has shown in the past. Its an area that, as mentioned before, has a vast range of types of dyno, qualified and un qualified operators, experienced and ham fisted tuners...big number chasers and smooth driveability persuers...we all like our cars the way we like them. I just like to be honest with mine....From the start I said I would be happy if I could make 300bhp, and Im very nearly there. No silly chips, just proper old fashioned improvements.

With regards to the dyno telling us what we want to hear...tut tut it doesnt. What I wanted to hear was that I had 300bhp and the smoothest running s4 around with no issues. However, I got the truth. That it was, as I feared, running incorrectly as the system was in some respects not working with the rest of the system in harmony. But because of this, I now have a much improved drive now. Yes there is still room for improvement, the few items I mentioned to do still. But I believe I have made more efficient the system that is in place, without chasing silly figures.

The true test is to gather several Esprits and make a day of it. Im sure that there would be some suprises...both good and bad...

[CHANGES]

Luke,

Please don't take my remark personally, I was generalising , when the question of dyno validity came up on my 412 thread it consumed pages and eventually laid scorn on my results. Quite unfair really.

Double Tut Tut on what you want to hear....

In general.

Darren's results give valuable data to all those who have bolted on mod's ...I think this is the first time an accurate dyno has be used to see what influence these mod's have. Although honest gains were made , it took a dyno to set them up and even then they fell short of so many claims that have been made on what they should produce...

What Darren has shown hear is the true results of these mod's and how important it is to balance them in on a dyno otherwise they are never going to benefit your performance.

Darren is now also aware of area's that could be improved to refine the outcome, Details he would never have known about unless he had dyno'd the Esprit.... I am sure once all these little points have been addressed he will achieve the 300 bhp goal..

[sailorbob]

I was curious if the MAP was being measured at the same place as where the standard system is. The standing start overboost is activated by revving the engine whilst the vehicle is stationary (e.g. 5k rpm for most ecus). The overboost is then allowed for a short period which would allow time to get to fourth for the dyno run.

I was inquiring about these things because you are showing more boost than the stock ecu can measure.

Edited June 22, 2012 by sailorbob

[dodge1979]

I see your point derek. Yes it was using the same takeoff to measure the boost. Obviously the stock ecu can only read up to 1bar, however the dyno can read far higher and more accurately. My boost was at 1.1bar. Now to explain, before I bought the car it had been fitted with a brand new turbo/actuator assembly at a lotus dealer. The car then travelled a total of 200 miles or so before being laid up for some time prior to sale. So the was not altered by myself at all. This has been checked for its correct functioning and as the ecu thinks its an s4s, the boost will be slightly higher than standard s4. The chances are its been set to 1bar by the dealership as accurate as they can, but only with a dyno this accurate will you confirm its true figure.

The use of gears 1,2,3 are only for warming up the engine and running down. Forth is used from its lowest rev range right up to the limiter to gain the data. No pre revving or overboost function is used to gain a modified or inaccurate data log.

I probably should add with regards to having tested the functioning of the actuator, I did this as per the workshop manual and found it to be as per spec, correct pressure for opening and correct adjustment of the actuator rod..

[NMS]

For those on the forum that seem to doubt Northampton Motorsport's credentials, perhapse this will help.

http://www.digitaltr...-expensive-car/

[CHANGES]

What a machine.... I know you have many similar exquisite and very expensive cars through your workshops

but that is just outstanding.....

I see cooper is in his element , never happier than when he is playing with a $35,000,000 classic...

Funny ....and you all still take time to help and advise us Esprit owners... .

Keep up the good work..

[NMS]

Thanks Dave.

I see you have been busy with the Esprit.

We have a really nice modsports Elan in for dyno next week so i will post a few pics for you.

[dodge1979]

I wonder if it.glows in the dark too..........

As a little update to what I posted..ive been through the small tweaks needed, turbo boost hoses have been replaced witg new silicone items and mikalor clamps used to seal them. The plenum and plenum nozzle were removed and new gaskets fitted along with wellseal to ensure there absolute pressure tight. After testing I cqn confirm all the minor boost leaks are cured...which brings me on to wonder how many other esprits out there have similar boost leaks, which the owner doesnt know of?

To be shown these things in clarity and how they affect the performance of the.engine in real time is a.fantastic opportunity and id urge anyone to take the time out to perfect their cars...even if you think your running fine...

[dodge1979]

Well guys, as an update to this thread from last year, I revisted Northampton Motorsport last wednesday (at the same time Dave was testing the new manifold design...) with a view to checking over the tweaks made since the last visit. To briefly recap for those not wanting to read back, I was making (by the end of the session) 292bhp having discovered various fuelling issues and boost leaks..mostly these were recitified on the dyno and tested again, the final boost leaks were sorted out at home with the fitment of better quality clamps and hoses.. along with the plenum chamber being resealed with, again, a new gasket and the addition of Wellseal to ensure a perfect seal...

 

Recently, I had also decided to remove the freeflow sports cat and replace with a de-cat pipe. This would also have changed the characteristics of the engines performance, requiring the fuelling to be checked over to ensure it was set correctly and to satisfy my curiosity that all issues were sorted and what the final figures were....so what differences do the decat pipe make? In terms of driving 'feel', it was apparant that the hesitation around 2800rpm had all but dissapeared which means I was expecting to see an increase in low to mid range torque as a result...

 

We made three runs on the dyno, first run again is to set the start data as a reference of how the engine is performing. This started with very promising results, she made 300.6bhp first time round! Very happy to have seen the 300 mark reached...I wanted to also test whether all the boost leaks were sorted, which indeed were, and to test whether the dump valve was leaking any boost under pressure..by the use of a blanking plug in replacement of the BOV, a second run was made, resulting in the same figures as before showing no leakage of boost, so it was refitted and the fuelling was tweaked ever so slightly up to adjust suitably for higher revs, as it was running just a fraction weaker at the high revs...this was assumed to be as a result of the decat allowing the engine to breath more freely.

 

The third and final run was to gain the final figures. Again 300.6bhp was achieved, along with 296 lbft of torque. A satisfactory set of figures. Now the true indication of how the decat pipe has altered the engines performance can be seen in the graphs Ill attach shortly. To run you through them, the red lines are the previous run from last year, the black line is the most recent run from last week. On the BHP chart, you can clearly see an early increase in power with a very smooth and steady climb, surpassing the previous BHP peak point at 5500rpm and increasing up to peak at about 6250rpm, then droping off smoothly, instead of the previous 'flat' peak and run off.

 

With the torque chart, it is imediately apparant that an increase in low to mid range torque has been achieved, as expected. The sharp climb from just below 3000rpm to 3300rpm where it peaks before slightly dropping off is a clear explanation of why the slight hesitation previously present has now vanished, and whilst it does drop of slightly its still higher than previous before it gains a steady climb upwards, again with a smoother peak reached just below 5000rpm, some 500rpm earlier than previously, then falling off smoothly, but still higher than previous.

 

So, for the time being, this data shows what is truely achievable (regardless of product claims) with the right mods, and most importantly the correct setup having been made and then tested. 300BHP is a goal that can be reached, without using untested 'chips' to merely pour fuel in and up boost. In the method and manner that I have done, you can have a strong, reliable and most importantly extremely drivable Esprit.

[MartinL]

Well done Darren (and Northamoton motorsport) i hope you are pleased with the result............. but could you keep up with Dave on the run home?? Have you arrived at a better "driving" car and in real terms what difference is there in everyday use ??

[palmergeddon]

Good read Darren. I will have to make do with 280bhp for now - but you are right, sensible mods is the way forward, not just chipping as a quick fix.

[lotusesprit1]

Very interesting results, thank you for posting, my esprit has some similar modifications done by a previous owner. There is definitely a boost leak as I can hear it on acceleration I suspect the dump valve. I am tempted to remove it altogether as it was not there when new.

 

I need to identify the chip I am running and fix a few other things but think  a trip to Northampton is definitely on the to do list.

[dodge1979]

Martin...indeed I could keep up with him! Says something for the bad weather we had that day that worked in my favour ;-) but seriously, I feel I now how a much improved experience. Lower throttle response is much improved with quicker spooling of the turbo, the well known lag is much reduced creating a smoother increase in power. Light to mid throttle response and use is also a smoother almost easier drive. This can be translated across to the graphs ive posted above to see how and where these benefits have been made over standard. But most importantly of all I know that every single change from standard, whether its minor or major has been tested, checked, adjusted and confirmed that it is working to the best, most efficient standard that is possible within the confines of the set-up ie, the limitations of the GM ecu system and exhaust manifold. Also as important is that I know reliability and strength of my unit is excellent. As mentioned earlier in the thread, im not a fan of 'chipping' the ecu...these replacement chips from well known suppliers cannot be classed as a safe way of gaining power without potential long term damage to the engine, and also as such how can they have been developed to perform alongside other modifications that we do...whereas if you make your modifications work together correctly, youll end up with a far better package overall..

Ian, yours is not.to be scoffed at! When I drove it briefly last year, as I said at the time, I knew you had a really good one there..and thats the best base to start with to then carve it out to how you want your car to be...everyone likes their setup to be how they want it, but its easier to achieve with a good.basis...

And finally, lotusesprit1.. Sorry I dont know your name? Well, a quick question, does it sound a bit like a.supercharger winding up? That was my issue previously...which turned out to be the hoses leaking...the sound of the.pressure escaping was like a.scream! Get a.blanking plug to.fit temporarily to test your theory...if your local(ish) maybe I can help..your chip ID can be gained from using espritmon program, it will give you an eprom (i think) code in the top left then from that you can determine what chip is fitted. Finally, keep a dump valve fitted if your running a small turbo..ie SE/S4... It will help against it stalling between gearchanges...