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412 BHP...THAT WILL DO NICELY...... - Page 6 - Esprit Chat - The Lotus Forums Jump to content
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412 BHP...THAT WILL DO NICELY......

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Hi Buddsy,

I have not driven it yet, but on the dyno there was no lag at all ... this can be seen in the graph...The new ECU has turbo anti lag system built in as well as the flow factors..

Troy from N'hampton motor sport said when he took it on small drive it was very impressive .....no turbo lag was mentioned....

I hope to have it back in 10 days time and will give you a full breakdown on how it drives....both Good and Bad points .... after all , that is what it is all about , Drive-ability...

Edited by CHANGES

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Upgrade today to remove Google ads and support TLF.

Continues to be very impressive.

..... you do not want to deploy anti-lag..... oh no :scared:


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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As promised, I have posted in the Forum "Garage" section (mod: Intake Flow & Plenum Volume), few pictures of the IM diffuser “Moustache” diverter, which equalizes filling of the cyl #1 and #4.

Dave, could you please post couple of pics from the latest batch I have sent you?

Also shown, there is the Commemorative Michael Rodrigues Plenum Expander, milled of the 1" billet aluminum plate, which adds 60 cu in to the overall plenum volume.

It has a positive effect on cylinder filling in higher rpm band, as it acts as an in-line Helmholtz resonator coupled with the cylinder cavity volume. (See: SAE Paper Number 983045. Analisi e simulazione di sistemi di aspirazione accordati al motore. D. Bortoluzzi, A. Doria. Department of Mechanical Engineering, University of Padova,Via Venezia 1 35131 Padova Italy).

FYI: Turbo lag time in sec= (Intake Manifold Volume , cu in, divided by engine flow rate at cruise speed, CFM) x2x(60/1728)

Assuming expanded plenum, like Dave's, Total IM vol=200 cuin + vol of the chargecooler and air pipe- that will give you the worst case.

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Unfortunately I could not lift the pics off your e mail John but nicked this off your garage pic's for this thread...

As you can all see from John's last post the calculus involved in volumetric modification and flow is a bit more than .....grind a bit out..!!! saying that the basic's are not that involved..

Some of the information John has sent me has been priceless , a classic example of collaboration between forum members to achieve desired results.. Thanks again mrDangerUS

JOHN'S EXPANDED PLENUM AND FLOW DIVERTER

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I understand the theory of increasing the distance between the inside of the plenum and the inlet trumpets, but why not just shorten the trumpets ? :book:


Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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Roger,

On carbureted cars, shorter trumpets would adversely affect the throttle filling. It would have a choking effect. FI Esprits don't have pronounced trumpets. They have 5x8mm "bump" around the throat inlet. This area is asking for correction.

The ideal air inlet shape should have trumpet OD=3d and radius of arc=d, where d is the throat diameter (40mm for FI cars).

Plenum volume augmentation "stretches" the torque curve and aids cylinder filling via accoustic supercharging. The peak of the filling index could be moved across the rpm range by manipulating the plenum volume and it's geometry.

Edited by MrDangerUS

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OK, that's starting to sound similar to the principle of bagpipes. :huh:


Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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"...and aids cylinder filling via accoustic supercharging..."

Sounds exotic, John. Is this perhaps something to do with soundwave "harmonic resonant frequencies" or the like? And is it something that is also subject to "calculation," or more trial and error methodology? Feel free to jump in, Dave. It's your thread after all! :)


Being second is to be the first of the ones who lose.

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Hi all,

If we go down this road and start discussing intake harmonics I fear this thread will turn into an open university paper.....Although this would make fascinating reading to a few, it will have little or no relevance to the members wishing to gain a few extra HP...

However to clear a few points in basic terms...... Tuning the intake side on an engine is very technical and does involve the calculation of resonating frequency's . because an engine works through a rev range , not at one fixed speed , the perfect tuning would involve constant physical changes to the intake system to maintain perfect tuning....as this is not practical a single tuning point within the rev range is arrived at....usually around 4000rpm ....But not always..And it is not often where the engine has its most power....buy altering the length / volume of the induction side of the engine you will alter the position in the rev range....This can also be changed by the valve timing , hence the introduction of variable valve timing...and Its far more more relevant on a N/A engine,

Calculating and modelling the intake harmonic, then estimating the VE and final engine output is a computational intensive task, manufactures employ programs to do this . but even then it only provides a rough estimate based on the pure numbers.............In a nut shell its calculated trial and error with experience based on methodology.....

SO ....as most of our engine induction system is fixed by design , there is not a lot that can be done without major changes......However there are some area's such as the plenum that can be addressed and will enhance performance as part of a tuning package....

As far as my project goes, I concentrated on the basic theory ..air flow = power production... in my opinion a turbo engine is more about flow than resonant tuning...

That is why i spent so much time on the flow / VE side of things .....it is easier to calculate and understand with massive gains to be had... But you must never ignore the other values in your work as they all have an effect somewhere in the cycle.....

I just read this back and nearly fell asleep , it started to sound like the dyno discussion... :offtopic::popo:

Anyway ... I should get the Esprit back this week and the road tests can begin..... :thumbsup:

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For those who would like to learn more about inertia charging and IM function as a resonator:

http://www.dinamoto.it/dinamoto/8_on-line_papers/risuonatore/risuonatore.html

http://www.dinamoto.it/dinamoto/7_MDRG_papers/_MDRG%20Papers%20in%20PDF%20format/1999_05%20Analysis%20and%20simulation%20of%20engine%20tuned%20intake%20systems%20MODENA.pdf

Jameson, Renee T., and Hodgins, Patrick A., ‘Improvement of the Torque Characteristics of a Small, High-Speed Engine Through the Design of Helmholtz-Tuned Manifolding,’ SAE 900680

Kong, H. , Woods, R., 1992, “Tuning of Intake Manifold of an Internal Combustion Engine Using Fluid Transmission Line Dynamics”, International Congress & Exposition, SAE,February 1992

K Banisoleiman, L A Smith, B A French , The interaction of diesel engine turbocharging and tuned inlet manifold systems under steady state and transient operation , Subject Proceedings of the Institution of Mechanical Engineers 1847-1996, Volume 205, Number A4 / 1991, Pages 269-281

http://muhserv.atauni.edu.tr/makine/akifceviz/pdf_files/A/e.pdf

http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000133000001012801000001&idtype=cvips&gifs=yes&ref=no

And on the subject of VVIM-s:

http://www.dinamoto.it/dinamoto/7_MDRG_papers/_MDRG%20Papers%20in%20PDF%20format/1998_03%20The%20effect%20of%20tunable%20resonators%20SAE.pdf

Edited by MrDangerUS

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Thanks for the explanation, Dave. You're a real trooper!

And thanks also for the links, John.


Being second is to be the first of the ones who lose.

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Hi Dave,

I met you at Northampton motorsport when you were carefully removing your rear 1/4 windows lol

Very nice result and a stunning looking car.

As far as Im concerned NMS RR is one of the most accurate in the country (and I get to see results from Rr's all over the country).

Let me know when you need some more power, there's more in there with a cam change ;)

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I have ideas when I eventually need to rebuild mine, but I'm thinking more 350-380 hp. My question is at what point does the frame start to distort, because if you're getting all this power to the ground and not just wheel spinning, something has to give, the frame and the casing of the gearbox is way beyond what it was designed for. I have no idea what my output is, it's pretty much a standard 88 turbo with "caressed" induction, and boost 8-9psi but not much comes past me.


Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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I met you at Northampton motorsport when you were carefully removing your rear 1/4 windows lol

Very nice result and a stunning looking car.

As far as Im concerned NMS RR is one of the most accurate in the country (and I get to see results from Rr's all over the country).

Let me know when you need some more power, there's more in there with a cam change

Thanks Mat . we must have a chat when its all done , I am always looking for improvement possibilities.. I'm glad you mentioned about how accurate NMS dyno is , as you will have read not everyone wants to except the figures.......

Roger... Thanks for you observation on the structural integrity.....I agree there are areas that would need attention if you were racing this sort of power as the stresses would exceed design on regular basis... however the standard chassis is quite impressive and is well capable of handling the power for basic use and the odd track day...

But just to make sure, I have made a few changes to cover the bases. The whole car spec has been upgraded top to bottom to accept what ever i throw at it....

The road testing should show up any areas of weakness and i will post them as they appear with solutions.....Hopefully there wont be any ....

I think you will be surprised how much can be dialed into these Esprits without to many issues...

Edited by CHANGES

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UPDATE

Early on in the thread i mentioned that at high revs..6500+ we were experiencing fuel pressure problem, we put it down to the size of the pipes in the tank . but as we had achieved 412 bhp it was going to be left for now as it was probably enough power anyway. ..

However it seem the Sytec ITP 116 fuel pump that cost me £125.00, has joined the list of parts supplied under spec requirements that is wrong.....!!!!

Whilst trying to map the main section it was noticed that the fuel rail was very very hot....not good.!! the pump was at its limit and causing aeration of the fuel at pressure required...

If we lower the pressure it will function ......But.......thats not really right is it...... SO ...lets make a few CHANGES......

Initially we said fit bigger pipes into the tank and an external pump to supply all the pressure / volume needed.....

Unfortunately when Cooper the engineer studied it , he said the deep tank design will create a problem with pulling the fuel up in a large pipe when tank is less than half full...and may cause problems with purge start up......

The solution...... The existing pump will supply a 1.5 ltr Swirl pot.... this will then supply the large external pump / high flow filter etc.... The beauty of this is we do not have to mess with the original tank set up.....Just add parts and re-route the fuel system......

This is a diagram of proposed new fuel set up

post-10519-0-31989600-1307276580_thumb.j

This in its self raises the question on how did other people achieve over 400 bhp.....I have had to make so many changes to standard to make this possible....

I have been very open and as accurate as possible about all i have done , This is an information gathering project and i know others are trying the same, but Is there information out there that we are not a party too....??? If so Please share with us all to complete the picture and expand the options....

Dave.

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FINISHED ON DYNO.

Results

Well we have gone as far as we can for a road spec car , To introduce any more power will loose the smooth drive-ability which is the important focus of this project.....

We have fitted up the revised fuel system with very interesting results....

The larger pipes with the higher spec external pump can provide all the fuel needed at 3.5 bar as apposed to the old system that could not at 5 bar where it failed...!!

This has proved to be another area where volume and flow are quite critical to get the best results....

when we ran it up on the dyno with the new fuel system and different plugs with 0.020 gap, we instantly generated an extra 10 bhp. on the same settings as before....

We now can achieve and hold 1.5 bar (20.3) boost without issue...for max power output of 422 bhp...391whp... using the boost controller we can turn the power down to 385 bhp with a setting of 0.65 bar.....however due to the gas flow volume and the waste gate system , it creeps through the rev range increasing incrementally up to 1.1 bar at 7600 rpm....Although this is technically wrong it has the very nice effect of a gradual introduction of boost without the big power surge..... Not bad and 385 to boot.....

The mid range mapping is all done , just need tidy up wires an pipes now....

I will pick the Esprit up on Tuesday the 14th and finalize the fittings, Once i put parts back on ..Tailgate. race floor. and of cause the rear wing.. ( no comments Roger.....its staying[ )

i can road test just before the Gaydon super car show. which will be its first real outing....

I will post pics of the ECU and fuel mods once it is back , before it all gets hidden from view....

For now here are the Final dyno results....Any other data anyone wants , just ask and i will down load when i pick it up........

post-10519-0-52071100-1307728884_thumb.j

post-10519-0-62201400-1307728923_thumb.j

:whistle:

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I've been reading this topic with much interest. It's simply fantastic!

I hope you won't run into too much problems, as reliability is a key issue to me personally. I hope you keep us updated.

Once again congratulations on what you have achieved!


Calypso Rose Rules the World!

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Congrats Dave. Looks good!

FYI: here is another pioneer, Stefan, who took Esprit to 500!

http://www.thelotusforums.com/forums/index.php/topic/18893-project-sport-500/page__st__180

Wow!

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Hi John,

I have been following Stefan's thread for some time with Great interest , although it seems he has achieved great figures , i am keen, as he will be , to see what the true power / torque is on a calibrated dyno.....I feel what he has figure wise is only an approximation at the moment.... Unfortunately the thread has gone quiet on the subject after he said he was going on a dyno, The read out results would be great to see.....I am sure he will post them on his thread soon...

Gary kemps engines are well known power units, and very impressive....This 2.6 ltr unit should produce his targets as there is no substitute for cc when going for out and out power.. I am just not sure how it can be achieved with the standard ECU and a chip....and still be used comfortably as a daily driver....!!

However, we must not draw too much comparison between the two projects . They both have very different specifications with very different objectives, Each will stand on its own merits and hopefully provide useful data for the Forum membership and enthusiasts..... :thumbsup:

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Hi John,

I have been following Stefan's thread for some time with Great interest , although it seems he has achieved great figures , i am keen, as he will be , to see what the true power / torque is on a calibrated dyno.....I feel what he has figure wise is only an approximation at the moment.... Unfortunately the thread has gone quiet on the subject after he said he was going on a dyno, The read out results would be great to see.....I am sure he will post them on his thread soon...

...and the accused has become the accuser. :innocent:


Luke Colorado, Super Spy.   -  Lotus Owner No Longer

1987 Zender Widebody 560SEC | 1994 Lotus Esprit S4 | 2013 Honda Fit EV (#269)

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...and the accused has become the accuser. :innocent:

Tu Chet :whistle:

'' All we want is the fact's ma'am , just the fact's ''.... ( Joe Friday , Dragnet ) :harhar:

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