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Old 10-14-2015, 12:47 PM   #21
Sl0wlane
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Default Re: Help me choose a turbo for my K20 Lotus Elise

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Originally Posted by AngryScotsman View Post
Did you ever finish this? Any dyno graphs?

Curious, since I'm thinking of going GT3582R twin scroll with a K24 and not quite sure how well that'll work.
Finish this? I've only just started

Turbo purchased, engine spec almost finalised, build starting within the next month or so.

I'll update this thread when I have anything to report!
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Old 10-19-2015, 11:58 AM   #22
Sl0wlane
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Default Re: Help me choose a turbo for my K20 Lotus Elise

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Originally Posted by LotusElise View Post
I wouldn't do that...the Elise cooling cross section area is limited, also the clearance space. A Exige body would be a better one for that. But as mentioned above, there are possibilities ...maybe you have access to E85, which would be great, as the charge cooler wouldn't get that big for the same knock margin
I think I want to keep the Elise body, at least the rear clamshell, however I know I will have to lose the boot and probably have to open the area between the tail lights for cooling, sadly no E85 here - just 100ron "super" unleaded.

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Originally Posted by LotusElise View Post
In terms of drivability I would choose more SC (http://www.tts-performance.co.uk/#!lotus-elise/celz) than TC...same peak power, just a bit lower torque line below peak power...I am convinced the TC Elise would be fun at fast tracks like "Grüne Hölle" (Nürburgring)...for me hill climbing is furthermost application with slow corners, great VS band from 30 to 200 km/h, therefor a 300 BHP NA is the my way...SC could be next stage .
Yes, rotrex SC was a choice I looked at, and no doubt easier to drive, and due to traction probably faster on a circuit... But, I like turbos, and this is just a toy.


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Originally Posted by LotusElise View Post
Which gear box inserts do you use? I would recommend stronger everything (e.g. http://www.kmodperformance.com/K-Ser...NSMISSION.html), at least for 1.-4....as those 400+ Nm-guys to often has broken teeths, even with that light car, the gear switch dip in torque is nearly the same: huge and like a hammer blow for the notched impact strength of the teeth (tip in retard, gear related boost a.s.o. are good technologies to reduce that, but reality shows always a need for higher requirements levels because of imperfect human being )
I don't plan on drag racing, maybe the occasional fast launch.. But with standard (225 section Toyo R888) rear tyres, I think the tyres should slip before the gearbox gets overloaded (perhaps).. At any rate the gearbox is being built for this use.

Any other insights? You appear to be very knowledgable, I would love your input on cams, compression ratio, do I NEED to build with sleeved block for this (approx 5000 miles per year, expect rebuild year 3), inlet manilfold? (I am looking at the skunk 2 ultra)... Any other info much appreciated!
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Old 01-07-2016, 06:03 AM   #23
Sl0wlane
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Default Re: Help me choose a turbo for my K20 Lotus Elise

Still hoping I can get some more advice, if you all feel like it?

OK, my engine spec is now:
  • K20a2 with Deck extension to provide 2.5l capacity
  • Darton Liners
  • 87mm Forged Pistons (Clockwise spec)
  • K24 crank
  • Ported head - mainly on exhaust ports
  • Uprated valves - main effort to exhaust valves
  • ODGT3579HTA Garrett Turbo
  • Jenvey Turbo plenum with 70mm DBW TB
  1. My engine builder is suggesting 10:1 compression ratio - is this a good move? (He suggests limiting boost to around 1 bar)
  2. My engine builder is suggesting 8 injectors, 4 standard k20a2 injectors, and 4 larger ones used at high boost / RPM - is this really required, could I use just 4 of the ID 1000cc injectors? (He hates the "RC" branded injectors).
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Old 01-07-2016, 10:05 AM   #24
LotusElise
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Default Re: Help me choose a turbo for my K20 Lotus Elise

Quote:
Originally Posted by Sl0wlane View Post
...your input on cams...
Not able to answer the question before MAP/MEP is known, I would recommend smaller cams to start, like the stock ITR cams. Those are ready to power up beyond 500 whp with the right engine setup. Also aftermarket cams like the S2U1 are a safe bank to start with if you like S2 cams.

Quote:
Originally Posted by Sl0wlane View Post
...compression ratio...with sleeved block...
Stock block can be used for your power and application goal (500 whp, funny DD) within a 86x86 engine, static CR of 11.0:1 is good to start (s. D-Rob's TC'd K20 built made 697 whp on E85).

Tune it carefully, as the stock pistons are casted pistons which aren't fans of knocking combustion, those casted pistons are a bit more brittle than typically forged ones. Your tune quality = your engine durability.

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Originally Posted by Sl0wlane View Post
  • K20a2 with Deck extension to provide 2.5l capacity
  • Darton Liners
  • 87mm Forged Pistons (Clockwise spec)
  • K24 crank
  • Ported head - mainly on exhaust ports
  • Uprated valves - main effort to exhaust valves
  • ODGT3579HTA Garrett Turbo
  • Jenvey Turbo plenum with 70mm DBW TB
Some questions to it:I see you support by head work the above mentioned pressure ratio , this will definitly help to lower the pumping losses and reduce residual gas content.

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Originally Posted by Sl0wlane View Post
[LIST=1][*]My engine builder is suggesting 10:1 compression ratio - is this a good move? (He suggests limiting boost to around 1 bar)
That CR is very safe within a 99x87 TC engine if you use RON = 100 fuel (about 94 octane). You need just about 35 °C cooler MAT to run 11:1 at equal knock limit. Your MAP will be about 2.3 [email protected] whp or 1.3 bar of boost according to my conservative and simple VE calculation model.

Quote:
Originally Posted by Sl0wlane View Post
My engine builder is suggesting 8 injectors, 4 standard k20a2 injectors, and 4 larger ones used at high boost / RPM - is this really required, could I use just 4 of the ID 1000cc injectors?
Expensive not really needed solution as a proper set of 1000 ccm injectors, running at 81 % duty [email protected] whp with pumpgas or 100 RON fuel. He may aim a two line system to better part load control, but todays 1000 ccm injectors (balanced!) are sufficient enough too pass emission test too.

Of course, a second injector line, placed more far from intake valve would help to cool the charge, it is just a question of around +1000 € for runner adaption, bracket, line + extra time for installation + extra time on the dyno + extra nerves when tuning .

Which controller type/brand are you going to use for it?

Markus

Last edited by LotusElise; 01-07-2016 at 10:07 AM..
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Old 01-07-2016, 11:52 AM   #25
Sl0wlane
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Default Re: Help me choose a turbo for my K20 Lotus Elise

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Originally Posted by LotusElise View Post
Not able to answer the question before MAP/MEP is known, I would recommend smaller cams to start, like the stock ITR cams. Those are ready to power up beyond 500 whp with the right engine setup. Also aftermarket cams like the S2U1 are a safe bank to start with if you like S2 cams.


Stock block can be used for your power and application goal (500 whp, funny DD) within a 86x86 engine, static CR of 11.0:1 is good to start (s. D-Rob's TC'd K20 built made 697 whp on E85).

Tune it carefully, as the stock pistons are casted pistons which aren't fans of knocking combustion, those casted pistons are a bit more brittle than typically forged ones. Your tune quality = your engine durability.


Some questions to it:I see you support by head work the above mentioned pressure ratio , this will definitly help to lower the pumping losses and reduce residual gas content.


That CR is very safe within a 99x87 TC engine if you use RON = 100 fuel (about 94 octane). You need just about 35 °C cooler MAT to run 11:1 at equal knock limit. Your MAP will be about 2.3 [email protected] whp or 1.3 bar of boost according to my conservative and simple VE calculation model.


Expensive not really needed solution as a proper set of 1000 ccm injectors, running at 81 % duty [email protected] whp with pumpgas or 100 RON fuel. He may aim a two line system to better part load control, but todays 1000 ccm injectors (balanced!) are sufficient enough too pass emission test too.

Of course, a second injector line, placed more far from intake valve would help to cool the charge, it is just a question of around +1000 € for runner adaption, bracket, line + extra time for installation + extra time on the dyno + extra nerves when tuning .

Which controller type/brand are you going to use for it?

Markus
Thank you Markus for your reply!

I will try to answer as much as I can:

- Cams are engine builders own specification (clockwise of sump baffle fame) - low overlap, higher lift - safe for turbo use.
- deck extension is like a spacer that raises the deck by around the same amount as K24 (my engine builders own design and prototype) with darton liners
- yes this is the correct Jenvey turbo plenum, it will be joined to straight inlet manilfold with TB before plenum
- do you mean 10:1 is safe or 9.5:1 is safe - my engine builder says 9.5 is very safe and a bit too conservative (he says go higher to 10:1!)
- do you think 8 injectors will give better engine life (more miles) due to finer control at low load? (Less bore wash?)

Many thanks again!

Adam
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Old 01-07-2016, 01:44 PM   #26
nuk1ear
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Default Re: Help me choose a turbo for my K20 Lotus Elise

Quote:
Originally Posted by Sl0wlane View Post
Thank you Markus for your reply!

I will try to answer as much as I can:

- Cams are engine builders own specification (clockwise of sump baffle fame) - low overlap, higher lift - safe for turbo use.
- deck extension is like a spacer that raises the deck by around the same amount as K24 (my engine builders own design and prototype) with darton liners
- yes this is the correct Jenvey turbo plenum, it will be joined to straight inlet manilfold with TB before plenum
- do you mean 10:1 is safe or 9.5:1 is safe - my engine builder says 9.5 is very safe and a bit too conservative (he says go higher to 10:1!)
- do you think 8 injectors will give better engine life (more miles) due to finer control at low load? (Less bore wash?)

Many thanks again!

Adam
Why in the world would u use a deck extension? Just use a K24 block, theres more than enough mount kits to cater for the 22mm higher deck (I have an elise with a K24 in it too). I would go into the 9.x compression ratio, you can run higher ignition timing and ultimately have a safer engine. But this depends on if using E85 or just pump fuel.

Theres no need for a 'special' turbo manifold, just use an RRC or RBC and if you want to do something special cut it open and extend it to increase its volume, and while you're at it open it up to about 74mm for a 74mm throttle body. I had trouble fitting my increased volume RRC and modified the bulkhead on my car to fit it. The interior bulkhead plastics still fit so you cant tell.

Be very careful porting the exhaust ports, dont go crazy because the material is very thin to the water jackets. If you are porting the head, again, I dont see any reason to bother with the K20, just sell the engine to another lotus owner for a few thousand, buy a K24a3 (if ur europe or aus, or k24a2 if USA) which will cost biscuits and port that head and use that block. You will save untold amount of money by doing this and not bothering with ur crazy deck extension lol.

Is that an old GT series garrett? use a GTX........

8 Injectors is a good idea for idle quality and very low load emissions, but not required if you are not going to the extent of requiring testing for registration etc etc. You can idle fine with high capactiy ID injectors.

Last edited by nuk1ear; 01-07-2016 at 01:52 PM..
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Old 01-07-2016, 01:55 PM   #27
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Default Re: Help me choose a turbo for my K20 Lotus Elise

How mine sits:


Hacked up rear clam;


Bulkhead:
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Old 01-08-2016, 12:14 AM   #28
Sl0wlane
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Default Re: Help me choose a turbo for my K20 Lotus Elise

Thanks for the replies...

Nice build nuk1ear! The TTS / Ali-Tech mounts look lovely (but I read on Seloc you have had a bit of trouble fitting them?) - I'm using Dan HPEs mounts which are his own design in fabricated steel - but I do have the Ali-Tech shifter and gearbox mech with factory 211 cables.

A few more answers and questions:

1. The ECU is an EFI EURO 4 (http://www.obr.uk.com/pdfs/Euro%204.pdf) Dan (HPE) and Ian (Clockwise) recommended this and it looks very capable and motorsport homologated (traction, closed loop fuel & boost etc)
2. I know I don't NEED a special turbo manifold, but my research suggests a "twin plenum" design with diffused inlet will provide a more even air distribution across all the inlets (just check out any F1 or group B turbo inlet manifold, also read this: http://www.tdi-plc.com/tdi-proves-go...ey-evo-plenum/) - the bulkhead will be coming out completely and a new one fabricated.
3. Ian / Clockwise motion are very well known for building race spec K20/K24 engines so I would hope he knows how much material to take out of the exhaust ports
4. The turbo is in "HTA" spec and Owen Developments "M-Spec", it is the next generation on from the GTX series (http://www.owendevelopments.co.uk/pr...t_ODGT3579HTA/)
5. I don't really give 2 hoots about emissions, it's more about fine control at "road" engine speeds - I want the engine to last, so having loads of fuel pouring into it at low speed could lead to bore wash and a sump full of petrol - I wanted to know if the ID injectors are good enough to avoid this problem?
6. Sadly no E85 here - so just regular UK "super" fuel

Hopefully I can go and see Ian at Clockwise later today and talk to him about the "spacer" vs K24 block - I'm not totally convinced either, but perhaps he has a very good reason?!

I will also talk to him about compression ratio, I think it would be better at 9.*:1 and will be safer too - Ian is very concerned about the off-boost>on-boast transition in the Elise, and of course the higher compression ratio would help with this... but it will also limit ultimate HP... and I would like to see a WHP number starting with 5... if I don't I might as well have gone SC...

Cheers,

Adam.

Last edited by Sl0wlane; 01-08-2016 at 12:18 AM..
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Old 01-08-2016, 04:26 PM   #29
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Default Re: Help me choose a turbo for my K20 Lotus Elise

ive had good luck with my precision 5858. it made good power on 15 lbs on pump. also spools quick
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Old 01-09-2016, 06:36 AM   #30
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Default Re: Help me choose a turbo for my K20 Lotus Elise

Quote:
Originally Posted by Sl0wlane View Post
- Cams are engine builders own specification (clockwise of sump baffle fame) - low overlap, higher lift - safe for turbo use.
For safe use? Do you expect back fire into the IM due to MAP/MEP < 1 operation points? With the right choice of turbine and compressor map big (NA range) overlap increases power and and reduces response time during transient operation (dip in).

Quote:
Originally Posted by Sl0wlane View Post
- deck extension is like a spacer that raises the deck by around the same amount as K24 (my engine builders own design and prototype) with darton liners
Wow, thought this is technique from the B-series and maybe early K20'ies. Like nuk1ear recommended...
Quote:
Originally Posted by nuk1ear View Post
...use a K24 block...
..., those are pretty sufficient and have one sealing issue less . If you like to sleeve it, ok, but it is no must if you keep stock 87 mm bore. As I already mentioned, 500 whp could be put down by a TC'd stock 86x86 engine. Of course TC choosing and setup designing is a bit easier with a low speeder engine...and it will lower the load on every piece too.

Quote:
Originally Posted by Sl0wlane View Post
- do you mean 10:1 is safe or 9.5:1 is safe - my engine builder says 9.5 is very safe and a bit too conservative (he says go higher to 10:1!)
It depends mainly on the charge cooling capacity, MAT rules also as density is a function of both, pressure and temperature. With the right cooler a CR of 11.0:1 could be runned safely (with water injection very safely ). Of course ign. timing could be retarded refered to MBT as nuk1ear did mention, but it would be safe.

Quote:
Originally Posted by Sl0wlane View Post
- do you think 8 injectors will give better engine life (more miles) due to finer control at low load? (Less bore wash?)
Not really, bore wash is more likely if ign. timing retard demand would be ignored by more enrichment. Therefore a lower CR could help to reduce "over" enrichment too. Those big injectors may have a bigger variance at idle and low part load concerning there squirted mass, but spray pattern should be ok (same pressure, same nozzle, only shorter opening time). I was thinking of emissions as droplet size of that bigger injector is likely bigger (more CO, HC and a bit NOx).

Quote:
Originally Posted by nuk1ear View Post
...I would go into the 9.x compression ratio, you can run higher ignition timing and ultimately have a safer engine. But this depends on if using E85 or just pump fuel.
Don't forget the charge cooling guys. About 35 °C less MAT is about 1 point of CR!

Quote:
Originally Posted by nuk1ear View Post
Theres no need for a 'special' turbo manifold, just use an RRC or RBC and if you want to do something special cut it open and extend it to increase its volume, and while you're at it open it up to about 74mm for a 74mm throttle body.
TC setups suffer more than NA engine on low balanced VE (cylinder [email protected] ~ (MAP - runner and port losses) x CR^1.38). So the in max cylinder pressure difference is much more bigger, knocking at a single cylinder by leaning is more likely! Balancing the VE is the key to power safe and efficient. The OEM IM supporting VE of #4 and let #1 starve, consequently you have leaning at #4 and overfueling in #1 as Lambda is mostely measured in the common exhaust section.

Quote:
Originally Posted by Sl0wlane View Post
1. The ECU is an EFI EURO 4 (http://www.obr.uk.com/pdfs/Euro%204.pdf) Dan (HPE) and Ian (Clockwise) recommended this and it looks very capable and motorsport homologated (traction, closed loop fuel & boost etc)
Nice piece...CAN bus, dual channel knock control, traction and launch control...a fine piece

Quote:
Originally Posted by Sl0wlane View Post
5. I wanted to know if the ID injectors are good enough to avoid this problem?
Let them balance/match together (documentated), this will help to avoid this. Shorthened oil maintainance intervall is duty anyway within a TC setup! When we are at oil talk, I recommend SAE40+, as TC'd run at a lambda of around [email protected], this means oil dilution is always there! Part load control is a function of squirt mass variancy, therefore let them match the injectors, as the bigger the injector the bigger the part load fuel mass differnce could be. The cycle to cycle variance of one injector should be ok to drive, ID uses BOSCH basic components, which are used in xxxx TC'd engines. There is a good change to have suffcient cycle to cycle variancy ...

Quote:
Originally Posted by Sl0wlane View Post
I will also talk to him about compression ratio, I think it would be better at 9.*:1 and will be safer too - Ian is very concerned about the off-boost>on-boast transition in the Elise, and of course the higher compression ratio would help with this... but it will also limit ultimate HP... and I would like to see a WHP number starting with 5... if I don't I might as well have gone SC...
Adam, you are talking about key criterias of a good TC setup: load transition and load operation point design. But this two are much more than just CR, as this is static, counting is what dynamic CR you will get, which residual content and which MAT. There are camshafts, turbine map, compressor map, exhaust manifold, MAT...things of great influence and much easier to replace as to change static CR of an engine. I saw 87x90.7 [email protected] psi doing 615 whp with a CR of 8.5:1, but also stock 86x86 [email protected] psi doing 500 whp, both on pump gas...there is no general recommendation of CR for it's alone, it always have to put in to coherence with the engine setup. So, let's talk about that

Markus
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Old 01-10-2016, 07:34 PM   #31
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Default Re: Help me choose a turbo for my K20 Lotus Elise

My old K20a2 9:8:1 with a PTE6262 ips kt-1's netted 410Whp @15 psi. 500wheel would need around 18 or so psi.
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