Turbonetics turbochargers

jon · Post by **jon** » Tue Jan 30, 2007 9:46 am

Hi veecee, as a matter of fact I have considered raising the compression ratio to around the 8.8:1 - 9:1 range as but would not want to go higher than than for fear of detonation. There are definitely a few pros to raising the compression ratio (quicker spool, lower boost less stress on the turbo, overall increased efficiency, etc...)

If you have any other points to add please do, pros and cons.

Time will tell I suppose, for now I gather info.

Good morning Dislex666, I read about the HorsePowerFreaks turbo kit over on bimmerforums, it looks insane but I am a little skeptical of american dyno read outs, they do seem to be generous compared to similar setups over here.

jon · Post by **jon** » Tue Jan 30, 2007 9:50 am

<a href="http://forums.bimmerforums.com/forum/sh ... 4174">Link to low boost high compression e46 m3 turbo kit</a>

Puls0nic · Post by **Puls0nic** » Tue Jan 30, 2007 12:56 pm

Hmmm, so ur low down torque and response gets increased, but at the cost of less power overall? could work, if ur into traffic and turns I guess.

interesting

Dislex666 · Post by **Dislex666** » Tue Jan 30, 2007 1:04 pm

ja but there's also heaps of other stuff that comes into play by messing with the stock comp.

I'm sure the calibrator will come tell us more in due time...

jon · Post by **jon** » Tue Jan 30, 2007 1:43 pm

Thought this was intesting:
"The compression ratio is a single number that can be used to predict the performance of any engine (such as an internal-combustion engine or a Stirling Engine). It is a ratio between the volume of a combustion chamber and cylinder, when the piston is at the bottom of its stroke and the volume when the piston is at the top of its stroke. The higher the compression ratio, the more mechanical energy an engine can squeeze from its air-fuel mixture. Literally, high ratios place increased oxygen and fuel molecules into a reduced space, thus allowing for increased power at the moment of ignition. Higher compression ratios, however, also make detonation more likely."

<a href="http://en.wikipedia.org/wiki/Compression_ratio">Full article here</a>, good old Wikipedia.

Hi Puls0nic, I don't understand your reasoning, please explain.

Talk about going off topic

veecee · Post by **veecee** » Tue Jan 30, 2007 2:50 pm

maybe the point is that you dont have to have a huge turbo, or even a t3, to make useable power!!!

so its still a little on the topic - i hope!

jon · Post by **jon** » Tue Jan 30, 2007 6:38 pm

veecee: As much as I hate to admit it I think you are 100% right

The more research I do the more I slowly lean towards a sensible <a href="http://www.turbobygarrett.com/turbobyga ... GT2860R</a> with a 0.64 A/R, damn you all with your common sense and logic

Puls0nic · Post by **Puls0nic** » Tue Jan 30, 2007 8:30 pm

O h sorry... sumtimes my reasoning is ...... not wellput.

I just meant that if u increase ur compression ratio then u have to decrease ur boost levels, to keep the same level of 'detonation' so to speak. Normally aspirated engines have a high compression ratio, thats y they respond so nice and instant, while a turbo'd motor has a lower compression ratio, but it has the boost to compensate for it. So, driving a turbo car b4 the boost kicks in, will not respond or perform as well as a similar car, with the higher compression ratio..... until u get to the RPM where ur boost kicks in, then its cool. So, I was saying, if u increase ur compression ratio, then u have to decrease ur boost... So now ur car would perform better b4 the boost, just like or similar to a N/A car, but when the boost does come, its not as big. Very similar to the difference between a big and small turbo.

veecee · Post by **veecee** » Tue Jan 30, 2007 10:25 pm

thanks jon - but its just ideas that have stemmed from the two years i've been driving my sx. i would prefer more low down power to a strong kick in the back, and i've always thought that you could still reach about 250kw with a higher compression ratio and lower boost!

pulsar - not always true though - turbo motors and n/a motors are built differently. if built right, and tuned properly, i dont think you have to sacrifice boost. unless you were compressing to 2 bar to start with!!!

the common thing is to keep the compression below 11.5:1 in n/a motors, yet often when a turbo motor is in full boost it reaches 15:1... so i dunno. why not just have an n/a motor that has 15:1. maybe because they dont build heads that can support that much airflow without boost - i dunno. maybe i'm starting to ramble again - dammit!!!

along the same vein (although it may go off topic quickly), what kind of power might an sr20det yield with a compression ratio of 9:1, 2 bar boost out of a t3/t4, with 4 1000cc injectors???

Dunn · Post by **Dunn** » Wed Jan 31, 2007 9:37 am

check the new speed n sound with the 1400 bakkie using CA180det with 1000cc injectors and almost 2bar

Puls0nic · Post by **Puls0nic** » Wed Jan 31, 2007 11:02 am

[quote="veecee"]the common thing is to keep the compression below 11.5:1 in n/a motors, yet often when a turbo motor is in full boost it reaches 15:1... so i dunno. why not just have an n/a motor that has 15:1. maybe because they dont build heads that can support that much airflow without boost - i dunno. maybe i'm starting to ramble again - dammit!!!quote]

Thats because a N/A car has to pull/suck air in, while a turbo car forces air in. The difference why a N/A car cant really go higher than 11.5 has to do with the mechanics of air. Try sucking in air when ur lungs are already full... not so easy. But a 15:1 is possible if u force air in, thereby helping it to 'overfill' so to speak.

I was just saying, if both the N/A and the turbo'd car had the same final compression ratio (i know, they wuldnt), then the 'starting' compression ratio of the turbo car has to be lower, to make up for the boost, and thats why a actual loss of power is in effect before the boost kicks in compared to the N/A car.

anyways, enough of this.... u'll need a very strong "bulletproof" engine to be able to run high compression and high boost! Althought it will be an awesome feeling to drive a car with that!!

veecee · Post by **veecee** » Wed Jan 31, 2007 12:52 pm

T-cam wrote:check the new speed n sound with the 1400 bakkie using CA180det with 1000cc injectors and almost 2bar

this is my point exactly. its awesome that he's using the engine, and its awesome that he has similar internals to me and that he's boosting 2 bar and its handling it, and its wikked that his conrods can handle that too - it gives me hope for my setup...

BUT... all that and he has 400hp. i wonder what the same thing on an SR20 would give?

i've heard of a south african vehicle running a 15:1 in n/a, and its friggin quick, but detonation preventative methods are in use aplenty!!!

and you right about the loss of power because of compensation for boost, and most people say that their engines are "bulletproof"...

what i'm getting at is that it i would sacrifice boost for compression if i had to do it again! also remember that cfm is important too. a bigger turbo will push more air in at the same boost psi, raising the final compression ratio and bringin the whole thing closer to detonation!

enough rambling now... SORRY!

Hennie Marais · Post by **Hennie Marais** » Wed Jan 31, 2007 1:31 pm

jon wrote:veecee: As much as I hate to admit it I think you are 100% right

The more research I do the more I slowly lean towards a sensible <a href="http://www.turbobygarrett.com/turbobyga ... GT2860R</a> with a 0.64 A/R, damn you all with your common sense and logic

on the CA18 it will boost nicely from 3000rpm. Same setup as mine. But I like big turbos, Had a T66 on my 7MGTE in my nissan bakkie, boosted only from 5000rpm but man, it made HP.

Dunn · Post by **Dunn** » Wed Jan 31, 2007 2:06 pm

veecee wrote:
T-cam wrote:check the new speed n sound with the 1400 bakkie using CA180det with 1000cc injectors and almost 2bar
this is my point exactly. its awesome that he's using the engine, and its awesome that he has similar internals to me and that he's boosting 2 bar and its handling it, and its wikked that his conrods can handle that too - it gives me hope for my setup...

BUT... all that and he has 400hp. i wonder what the same thing on an SR20 would give?

i've heard of a south african vehicle running a 15:1 in n/a, and its friggin quick, but detonation preventative methods are in use aplenty!!!

and you right about the loss of power because of compensation for boost, and most people say that their engines are "bulletproof"...

what i'm getting at is that it i would sacrifice boost for compression if i had to do it again! also remember that cfm is important too. a bigger turbo will push more air in at the same boost psi, raising the final compression ratio and bringin the whole thing closer to detonation!

enough rambling now... SORRY!

So true meneer,by the way has anyone taken on an MR-2 gts

veecee · Post by **veecee** » Wed Jan 31, 2007 3:30 pm

i wonder if, with a little less boost and a little more compression, if he couldn't get to the same figures in a much more streetable configuration???

hennie, welcome to the forum, we've chatted on others! not me, i prefer low down torque... kinda like this 200sx might have, even though i am not really a fan of v8's!!!

but i wouldn't mind an inline6 turbo!!!

no turbo lag there!!!