High compression 4e?

[turbojim]

lads is it not better to have a lower compression on a turbo engine as it will increase spool by creating more exhaust gases?? im confussed

 

[Sheldon]

lads is it not better to have a lower compression on a turbo engine as it will increase spool by creating more exhaust gases?? im confussed

higher compression will spool a turbo earlyer.. thats why on lower compression you will suffer response..

 

[Ted]

You state here 1.5 bar will be fine on a high compression engine, despite your example being of a LOW compression engine? I don't understand what you're trying to say here.

The thread is about HIGHER than stock compression, yours is LOWER and therefore irrelevant, unless I'm missing something crucial?

For those that are a little confused on the way compression is altered, a thicker head gasket will result in LOWER compression, dished pistons will result in LOWER compression. Combine the two and you will end up significantly lower than stock and will be sacrificing quite a bit of response and drive ability while gaining the ability to run a bit more boost before limited by fuel quality. Stock head gasket (once torqued down) is 1mm, thus the TRD 0.6mm head gasket will raise compression a bit.

As weakboy2 stated, a skim of the head (done to ensure a flat mating surface) will remove a small amount of material, this will also increase the effective compression ratio. Likewise removing material from the block will achieve the same thing.

A stock 4e-fte in good condition @ 8.2cr should see 180+ PSI on a compression test, a stock 5e-fhe @ 9.8cr will give you more like 210psi. This isn't exact, figures will vary slightly depending on temperatures, tester and your particular engine - they are primarily used as an indicator of compression ratio and engine condition. Over time as valves/rings wear the compression tester figure will drop, as long as each cylinder remains within a 5% tolerance of each other it's nothing to be concerned with.

you just wont listen will you? when i said high compression engine i meant high compression FORGED engine, not stock.

 

[steveep82]

I believe Ted is saying his engine is a highER compression than most of the forged engines thats are being built at this time. I would really recommend you get the smallest turbo you can to make the rough power you are looking for, a high boost hybrid would be great around these cornish roads, but i will say that you will get used to a td04ls power delivery, its just a case of driving differently and upping the rev range you drive with, as you have logged rpms on a ct9 i presume, you have been driving to the ct9s power band that is finished at 6k whereas the td04 will not be. I think a high compression turbo engine is probably bad idea unless you have a lot of money to throw at it, id keep it near to stock as its tried and tested by many, lowering the compression isnt needed on these engines though in my opinion unless you are going to run 2bar plus.

 

[clarkytrd]

so using dished forged pistons and bigger head gasket, meaning more air getting into the chamber, you guys mean this isnt the way to go???

why is everyone else using these when forging??

please shed some light on this, someone who know what they're talking about

thanks

 

[billybob]

so using dished forged pistons and bigger head gasket, meaning more air getting into the chamber, you guys mean this isnt the way to go???

why is everyone else using these when forging??

please shed some light on this, someone who know what they're talking about

thanks

really simple lad dished pistons lower the compression of a standerd engine meaning up can run bigger boost ,the higher the compression in an engine you wount be able to run big boost,if you put dished pistons in a gt engine running a ct9 you get a little more lag on it ,as if without dished pistonsbut again it comes down to which way you want the car to run and what power you want to acheive

 

[sx_turbo]

Im going to be either using a megasquirt, or an Emerald, so no worries there.

megasquirt is pintless, only has 12 mapping points, there good on old classic engines, or on cars as a piggy back.

the emerald needs the car to have a new wiring loom.

when i was looking into to getting one it was gonna cost me close to 3.5k, as it's best to get rid of the distributor, and raplace it with a direct fire ignition coil, and make a custom crankshaft sensor and bracket and pickup wheel, i was told that it could work with the distributor (emerald will have to write a new program for it) but it would work best without it.

also as for spool etc, i would highly recomend the hybrid ct9, been out in a couple of the tongs gt spec ones and there pretty dam good and give an awsome kick, they spool up loads quicker than td04 and although the td04 is good and quick i persoanaly feel that round country lanes the ct9 hybrid is better

 

[Sheldon]

megasquirt is pintless, only has 12 mapping points, there good on old classic engines, or on cars as a piggy back.

the emerald needs the car to have a new wiring loom.

when i was looking into to getting one it was gonna cost me close to 3.5k, as it's best to get rid of the distributor, and raplace it with a direct fire ignition coil, and make a custom crankshaft sensor and bracket and pickup wheel, i was told that it could work with the distributor (emerald will have to write a new program for it) but it would work best without it.

also as for spool etc, i would highly recomend the hybrid ct9, been out in a couple of the tongs gt spec ones and there pretty dam good and give an awsome kick, they spool up loads quicker than td04 and although the td04 is good and quick i persoanaly feel that round country lanes the ct9 hybrid is better

as far as i know you can use a different code and you will have more then 12 mapping points.

 

[Fatman]

you just wont listen will you? when i said high compression engine i meant high compression FORGED engine, not stock.

Listen to what exactly? You never mentioned ANYTHING along those lines. I can't listen to what you don't say.

Quite aside from the fact that you never mentioned anything of the sort, what on earth has that got to do with anything? a 'forged' engine isn't always, nor should it be lower compression than the stock item.

clarkytrd, you can think of static cr a little bit like turbo sizing, it's a compromise between response and power potential. A low cr engine will have less likelihood of detonation or knock under very high boost levels, the major con is off boost performance will be worse. Just like with turbo selection, you want to select the smallest (or in this case, highest) turbo or cr that will allow you to obtain your goals while still keeping as much response/economy as possible. The stock cr is a great compromise and with stronger pistons (forged units) is capable of PLENTY of boost on pump fuel.

 

[Fatman]

megasquirt is pintless, only has 12 mapping points, there good on old classic engines, or on cars as a piggy back.

the emerald needs the car to have a new wiring loom.

when i was looking into to getting one it was gonna cost me close to 3.5k, as it's best to get rid of the distributor, and raplace it with a direct fire ignition coil, and make a custom crankshaft sensor and bracket and pickup wheel, i was told that it could work with the distributor (emerald will have to write a new program for it) but it would work best without it.

Megasquirt actually runs 16x16 fuel tables using MS2extra and they are (very importantly) fully interpolated in hardware. This means it's actually an infinitely variable map, if for instance you had a column at 2000rpm and 3000rpm with 10 and 20 VE, 2500rpm would be fuelling 15. Excuse the made up numbers. This is more than enough resolution, any more cells and all you're doing is wasting more time tuning.

3.5k in virtually any denomination is insane money for an ECU installed (save for perhaps a Motec or similar)

Total investment required into running a MS with the exact features and sensors you describe would be something in the region of $600NZD or £270 with a DIY install. Crank trigger sensor, custom crank pulley trigger wheel, wasted spark coils from an Evo or 4A-GZE are all easily achievable. Far easier and cheaper of course to utilize the stock timing gear of course.

A Link G4 or Vipec as they're rebadged over in Europe is compatible with the stock distributor based sensors and is world class in featureset and reliability if you're not interested in doing anything your self. I couldn't possibly imagine a situation where buying one and paying for professional installation would be over £1500.

 

[clarkytrd]

I will be running a Hybrid TD04, Wiseco 74.5mm Dished Forged Pistons, Scat Forged Rods, 1.2mm Head gasket.

Want to achieve around the 250BHP Mark, So what does everyone think?

Any recommendations.... idea's????

Thanks

 

[sx_turbo]

yeah i didnt know the megasquirt acted like that, was told different, and apologise for duff info

as for the 3.5k, this was ecu, fitting of the ecu (complete rewiring of all of the standard loom) and mapping.

there are cheaper options i dont know how they do things in new zealand, but over here everything costs so much money it's unbeleivable, not many tuners will fit a standalone ecu using the existing loom as they dont know the condition of it.

 

[Phil]

to be honest id aim for stock compression clarkey, and if you want big horsepower/boost run arp headbolts.

lower compression is safer at high boost with less chance of detonation but slower spool initially.

Phil

 

[Fatman]

yeah i didnt know the megasquirt acted like that, was told different, and apologise for duff info

as for the 3.5k, this was ecu, fitting of the ecu (complete rewiring of all of the standard loom) and mapping.

there are cheaper options i dont know how they do things in new zealand, but over here everything costs so much money it's unbeleivable, not many tuners will fit a standalone ecu using the existing loom as they dont know the condition of it.

Not a problem, you would have been quite correct about the early MS1

In all honesty wiring in an aftermarket ECU isn't NEARLY as difficult as some might lead you to believe. If you've got a good head on your shoulders and access to good resources (such as the knowledge on this site) then it's very possible to install yourself. Also very possible to get a good enough road tune together yourself with some basic training and a wideband O2 sensor, certainly good enough to drive safely to the dyno. I couldn't comment on what things cost over there but 3.5k does seem mighty excessive. Buy the ECU, install it yourself and then book in for a few hours with a tuner on the dyno - I imagine it would be a great deal more affordable! Plus you get to learn a great deal about how it all works in the process.

As an auto electrician of mine said the other day, wiring doesn't just break unless somebody goes messing about with it. This is obviously not true for much older cars, they can do all sorts of bizarre things! If you can vouch for the originality of your loom and it all works as it should then there is no reason to go rewiring the whole engine bay.

 

[Fatman]

I will be running a Hybrid TD04, Wiseco 74.5mm Dished Forged Pistons, Scat Forged Rods, 1.2mm Head gasket.

Want to achieve around the 250BHP Mark, So what does everyone think?

Any recommendations.... idea's????

Thanks

You should easily manage that sort of power level with good engine management, to be honest you won't even need a hybrid td04. Using those pistons and headgasket you are going to be ending up with lower than stock compression, how much lower I couldn't tell you without some more detailed info on the pistons/head/block and everything else that affects static cr. Personally I would recommend running about the stock level, non-dished pistons should get you pretty close if they are an option.

 

[clarkytrd]

to be honest id aim for stock compression clarkey, and if you want big horsepower/boost run arp headbolts.

lower compression is safer at high boost with less chance of detonation but slower spool initially.

Phil

i will be running arp headbolts, and arp conrod bolts too

Tuning Devlopments recommended using a 1.2mm metal head gasket.

Most projects ive seen on here, they are using the exact same setup.

i cant get my head around this, block will be bored to 74.5mm, 1.2mm gasket, so obviously gonna be more air in the cylinders, so how am i lowering the compression? more air, more compression?? meaning more boost, quicker spooling??

thanks

john

 

[Phil]

yeah stock td04 is the best option for 250hp, a gt25 on its limits might make that aswell.

i wouldnt suggest a hybrid ct9, the best of the hybrids are almost replicating the power delivery of a td04, with reliablity a big problem.

how many smokey hybrids do you hear about? poorly rebuilt perhaps? poor materials used? they never seem to last the distance compared to a stock td04.

Phil

 

[Phil]

i cant get my head around this, block will be bored to 74.5mm, 1.2mm gasket, so obviously gonna be more air in the cylinders, so how am i lowering the compression? more air, more compression?? meaning more boost, quicker spooling??

bigger volume same amount of air, less compression.

Phil

 

[Fatman]

Here is an excellent explanation (along with a lot more technical info) for you clarkytrd.

http://en.wikipedia.org/wiki/Compression_ratio

In short, the compression ratio is difference between the volume of the combustion chamber at its largest and smallest. e.g the volume of the cylinder when the piston is at the bottom of its compression stroke is 8.2 times the volume when it's at top dead centre, the top of its stroke. This area above the piston is effectively made larger by dished pistons or a thicker headgasket (raising the roof as it were)

 

[clarkytrd]

Here is a list of things that will be done/used:


Wiseco Racing Low Comp Forged 74.5mm Pistons
Wiseco Racing Piston Rings, Pins and Clips
Scat Forged Conrods with ARP 2000 Connecting Bolts
Zep Metal Head gasket 1.2mm
New Complete Cambelt/Tensioner/Idler Kit
New ARP Head Bolts
New Toyota Full Engine Gasket Set
New Toyota Oil Seals
New Water Pump
New Toyota Oil Pump
New Thermostat
New Toyota Valve Stem Oil Seals
New ACL Bearings ( Mains, Bigends and Thrusts)
Block Professionally Rebored and Crosshatch Honed
Crank Checked + Balanced, Knife Edged If Needed
Cylinder Head Professionally Rebuilt
Block chemically Cleaned and Painted
Flywheel Balanced
Wepr Evolution manifold
Td04 Turbo Hybrid
Tial 38mm External Wastegate
Wepr Front Mount Intercooler
Wepr Screamer Pipe
Wepr Downpipe
HKS SSQV bov
Blitz Nur Spec R Cat Back System
NGK iridium heat 8 spark plugs
Walbro Fuel Pump
370cc Injectors
Emanage Ultimate
Apexi Air Filter Relocated Behind Bumper

+ Loads More!!