aidan46
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 posted on 24/5/12 at 10:32 PM |
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lowering compression ratio
I have a kawasaki zx10 1989 which I want to turbocharge. However I want to also lower the c.r to allow more headroom for boost. Dose anyone know if a
thicker head gasket can be sourced for this engine? Cheers
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dave-69isit
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| posted on 24/5/12 at 11:01 PM |
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how about a decompresion plate
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snapper
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| posted on 25/5/12 at 04:49 AM |
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Try Cometic they do just about any gasket in any thickness
You could fit 2 standard gaskets
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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daviep
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| posted on 25/5/12 at 06:12 AM |
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Much better solution is to fit a spacer underneath the barrels, this means you don't reduce the realiabity of the head gasket.
So buy 2x base gaskets, work out how much extra you need and then cut a copy of the gasket out of the correct thickness of shim steel. Sandwich the
the shim between the two gaskets.
(google " base gasket "
Cheers
Davie
“A truly great library contains something in it to offend everyone.”
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FASTdan
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| posted on 25/5/12 at 07:14 AM |
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I'm not that experienced in decomp plates but I remember a few years back when zetec turbo's were quite new, it seemed to be the general
concensus in the ford circles that if going decomp plate it was more reliable to bond the decomp plate to the block and use a single gasket.
I think thats what I'd be doing if I were using a decomp plate. stacked up gaskets and plates just dont seem right somehow.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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daviep
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| posted on 25/5/12 at 08:20 AM |
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quote:
Originally posted by FASTdan
I'm not that experienced in decomp plates but I remember a few years back when zetec turbo's were quite new, it seemed to be the general
concensus in the ford circles that if going decomp plate it was more reliable to bond the decomp plate to the block and use a single gasket.
I think thats what I'd be doing if I were using a decomp plate. stacked up gaskets and plates just dont seem right somehow.
With most bike engines (definately zx10) the engine construction is different from a car engines in that the barrells can be removed from the
crankcase, you then space the whole barrel up. The extra gaskets and spacers then only have to contain engine oil and crankcase pressure while the
cylinder head gasket is 100% standard.
Cheers
Davie
“A truly great library contains something in it to offend everyone.”
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snapper
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| posted on 25/5/12 at 03:49 PM |
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I like Davie's idea
Simples
The Cometic gadket is also simple if a tad expensive.
Most pistons can loose a mm or 2, not sure about bikes.
Bikes tend to have quite high compression to start with so it can mean a mix of solutions to reduce compression or new pistons.
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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aidan46
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| posted on 27/5/12 at 11:18 PM |
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I was thinking of using a second hand turbo from a car for this project. Is it possible to match a used car turbo correctly to a bike engine or any
other engine for that matter...or is it just a case of pot luck in choosing one that you hope will work? Ta
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iank
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| posted on 28/5/12 at 05:44 AM |
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Think about the volume of gas per minute, a 1 litre engine turning at 12000 rpm is the same as a 2litre engine turning at 6000 rpm.
So a car turbo from something like a saab should be fine.
Though I've never done it
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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aidan46
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| posted on 28/5/12 at 09:13 AM |
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Ok that makes sense i suppose! Ive also heard of some of the volvo and saabs which utilise a Light pressure turbocharger? Is this a safer option in
terms of mitigating against uncontrolled over boost?
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matt_gsxr
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| posted on 28/5/12 at 10:00 AM |
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With separate barrels then an additional spacer between the crankcase and barrels is a workable solution.
I got AndyW to waterjet two out of 3mm aluminium. Got a drawing from a chap on OldSkoolSuzuki.
Seems to work well.
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matt_gsxr
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| posted on 28/5/12 at 10:03 AM |
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regarding turbo sizing.
Volvo T5 ~6000rpm, 2.3litre
gsxr1100 11000rpm, 1.174litre
td04-16T works for me.
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kjouk
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| posted on 28/5/12 at 11:00 AM |
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Turbo sizing can be quite complex, you need to decide on what you want to get from the turbo in terms of bhp, spool up rpm, lag tolerance, drivability
etc and then match to budget for turbo & cooling. Knowing what you intend to use the car for would help a lot.
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aidan46
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| posted on 28/5/12 at 11:12 AM |
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Basically the engine will be used in an autocross car (similar to autograss). I want about 170 hp but i want as little lag and good throttle response
a possible. I know lowering the compression allows more for boost and greater horsepower but it increases the lag....So im kind of wondering which is
the best way to go and also what turbo to use? I can only afford second hand car turbo.
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Ivan
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| posted on 28/5/12 at 11:22 AM |
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quote:
Originally posted by aidan46
Basically the engine will be used in an autocross car (similar to autograss). I want about 170 hp but i want as little lag and good throttle response
a possible. I know lowering the compression allows more for boost and greater horsepower but it increases the lag....So im kind of wondering which is
the best way to go and also what turbo to use? I can only afford second hand car turbo.
I imagine that the ZX10 motor makes nearly what you want so maybe you should be looking at a low boost application which might work with standard
compression ratio so you reduce the lag hit.
First decide on exactly how much additional power you want then decide on boost levels needed then choose turbo. Unless you are very lucky any guess
without doing the calcs is going to be laggy, inefficient and not give you what you want and then there will be another unhappy turbo customer.
[Edited on 28/5/12 by Ivan]
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aidan46
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| posted on 28/5/12 at 11:58 AM |
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I inputted my info to the garrett boost advisor and it came up with the GT2052 turbo. Anyone use or know of this turbo? ta
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theduck
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| posted on 28/5/12 at 12:26 PM |
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I would look to start with a low boost setup on standard compression.
I know the renaultsport lads have quite a lot of success with this and compression on those is quite high as standard. Also seems supercharging
produces better results on otherwise standard engines.
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computid
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| posted on 28/5/12 at 12:30 PM |
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You might find this thread on BCF somewhat interesting with regards to turbo'ing a bike engine:
http://www.bikechatforums.com/viewtopic.php?t=206009&start=0
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daviep
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| posted on 28/5/12 at 01:10 PM |
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Try a U2U to "craigj" he turboed a standard ZX10 from memory I think he used a TD04-13c with standard compression.
Davie
“A truly great library contains something in it to offend everyone.”
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matt_gsxr
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| posted on 28/5/12 at 01:49 PM |
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www.bike-turbo.com may be a useful resource. It is still starting up, but there is a BEC section!
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kjouk
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| posted on 28/5/12 at 06:07 PM |
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The GT2052 looks like it might be a just a bit on small side, here are my calcs:
To make 170bhp (assuming base is 130bhp) you need ~7psi. This is calculated assuming turbo efficiency is 60% and intercooler is 50%. These are
conservative estimates to give some headroom. The calc for this is documented in a number of places, let me know if you can't find a
reference.
The NA CFM is ~200 cublic feet/min assuming 90% volumetric efficiency. The CFM into the compressor is ~300CFM (200CFM x Pressure ratio of 1.5).
Garrett use lb/min so we convert 300CFM to ~17lb/min assuming turbo outlet temp is ~80C based on 60% efficiency with 20C inlet).
If you look here on the compressor map you will see
at PR of 1.5 & lb/min of 17 looks to be just off the right side of the map so the turbo is running towards it's limits, assuming calcs are
correct.
This where some subjectivity comes in, my busa runs a TD04-16T, it's also a little on the small size for my use so it chokes at high rpm and
limits boost. This is not a big issue as moving up to a larger turbo would bring with it a later spool. What perhaps is an issue is being small I have
to run high boost to make the bhp, a larger turbo (with less back pressure) could make the numbers at less boost which would benefit throttle control.
Sadly always a compromise.
I'm no turbo expert but playing with the numbers and comparing compressor maps does give you at least some insight, always best to back it up
with real world experience though if you can find some.
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MRLuke
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| posted on 29/5/12 at 06:39 PM |
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quote:
Originally posted by aidan46
Basically the engine will be used in an autocross car (similar to autograss). I want about 170 hp but i want as little lag and good throttle response
a possible. I know lowering the compression allows more for boost and greater horsepower but it increases the lag....So im kind of wondering which is
the best way to go and also what turbo to use? I can only afford second hand car turbo.
You dont mean lag, you are talking about boost threshold, i.e. what rpm the turbo supplies boost at. Lag refers to the delay between the throttle
operation and the engine response once you are in the boost range.
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aidan46
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| posted on 29/5/12 at 09:03 PM |
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Thanks for the great feedback lads. Theses forums are brilliant.
Some of the Volvo and saabs use a light pressure turbo system which is supposed to have a quick spool time?
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40inches
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| posted on 30/5/12 at 08:33 AM |
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quote:
Originally posted by aidan46
Thanks for the great feedback lads. Theses forums are brilliant.
Some of the Volvo and saabs use a light pressure turbo system which is supposed to have a quick spool time?
The only difference between the SAAB LPT and HTP turbo is the software, both use the Garrett GT17. The HOT versions run the TD04HL.
I have a couple of TD04's from Imprezza's, I think they are 13g's. I no longer need them if you want one? PM me.
 
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aidan46
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| posted on 3/6/12 at 02:37 PM |
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Do ya think the standard gt1752 would
work for my application?
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