Engine Modification

**Pete LSD** · 10-10-2003, 08:04 PM

Has any car fanatic added a low-pressure turbo charger and intercooler to his/her car while retaining the original compression ratio?

Take the 2004 Civic sedan DX & LX models with a 1.7 Liter sohc 4 banger, as examples. The stock engine comes with a 9.50:1.00 compression ratio. Let's say I want to retain the original compression ratio and add a low-pressure turbo charger to it. Which type of turbo system should I look for when outrageous horsepower is not a requirement. Here is my requirement:

(1) Very high Peak torque at or above 150 lb ft
(2) extremely broad torque curve
(3) minimum turbo lag
(4) max horsepower at 150 or less

**cooler** · 10-10-2003, 08:09 PM

Originally posted by Pete LSD
Has any car fanatic added a low-pressure turbo charger and intercooler to his/her car while retaining the original compression ratio?

isnt that a lotta work for little hp gain?
I rather be blown

(I mean having a blower, i mean supercharged

)

**Pete LSD** · 10-10-2003, 08:20 PM

But supercharged engines are louder than turbocharged ones.

Originally posted by cooler
isnt that a lotta work for little hp gain?
I rather be blown (I mean having a blower, i mean supercharged )

**Traum** · 10-10-2003, 09:39 PM

Hey Peter. I'm a VW-fan, so I don't know too much about Honda tuning. However, I would strongly recommended you to talk to the guys from Kinetic Motorsport in Surrey if turbo-charging your Civic is what you want to do. From what I've heard on the VW forums, these guys are experts at turbo-charging, and they are a very friendly and knowledgable bunch.

Out of curiosity, I wanna ask why you are going the turbo-charging route. Slapping a turbo onto a non-turbo engine isn't exactly cheap, and there are lots of other tuning opitions available as well (installing a CAI is a cheap and efficient option). Furthermore, Honda Canada has recently announced the addition of a 160hp Civic Si sedan (see this link), so this is certainly something you might want to think about.

-Rick

**shiriblue** · 10-10-2003, 09:42 PM

why not just slap in an intake to gain a few hp while mainting the ratio?

**Pete LSD** · 10-10-2003, 10:01 PM

Well, I prefer fat torque versus very high revving engine

.

Originally posted by shiriblue
why not just slap in an intake to gain a few hp while mainting the ratio?

**shiriblue** · 10-10-2003, 10:39 PM

ahhh. keeping the ratio is going to be hard. its probably possible, but i think i'll ask my friends what they do. their prelude has more torque than hp so i'll ask them what they did.

**bigredlemon** · 10-10-2003, 11:10 PM

i'm no car expert, but i can tell you this:
a turbo will rob you of power at lower rpm (more air resistence) so you'll have less torque. A turbo won't kick in until 3-4k rpm so you'll have more power high end but less low end.

As for the pressure, is the SOLE purpose of having a turbo is to *increase* compression? If the compression is exactly the same, then the same amount of air and fuel will be in the engine, and the same amount of HP will be produced. Factor in the loss of HP due to the built, you've just paid $4K to have _less_ power.

**badrad** · 10-11-2003, 02:47 AM

Originally posted by Pete LSD
Well, I prefer fat torque versus very high revving engine .

you won't get that with a turbo - put in a supercharger instead. Or get yourself the SiR, the put in the blower... heheheh... sorry the blue one in the parking lot is badrad's.

**Traum** · 10-11-2003, 03:44 AM

Originally posted by bigredlemon
i'm no car expert, but i can tell you this:
a turbo will rob you of power at lower rpm (more air resistence) so you'll have less torque. A turbo won't kick in until 3-4k rpm so you'll have more power high end but less low end.

With today's turbo-charged engines, this is no longer true. Low-pressure turbos are very popular right now. You can find them in the VW 1.8T Golf/Jetta/Beetle/Passat, Audi 1.8T A4 / TT, the Volvo S40, and the Saab 93 Linear at least. In the VW/Audi case, the turbo kicks in at a mere 1950 to 2200 rpm (depending on model), and maintains an almost flat torque curve at 155 to 170-ish lbs/ft all the way up to 5500rpm or so. So depending on the type of turbo that PeterLSD wants to go with, a decent low-end and a powerful mid-range is certainly possible.

As for the pressure, is the SOLE purpose of having a turbo is to *increase* compression? If the compression is exactly the same, then the same amount of air and fuel will be in the engine, and the same amount of HP will be produced. Factor in the loss of HP due to the built, you've just paid $4K to have _less_ power.

Technically, I think automotive engineers only refer to the compression ratio as the ratio between the maximum cylinder capacity (at the bottom of the down stroke of the cylinder head) vs the minimum cylinder capacity (at the very top of the up stroke). As long as that is not changed, the compression ratio will remain the same. So a blower could be attached to cram more air (and therefore fuel) into the engine cylinder, they still refer to the compression ratio as the max vs min capacity.

-Rick

**cooler** · 10-11-2003, 05:32 AM

peter lsd, if you want cost effective flat torque curve, stuff a v6 in it.
Try and true auto/bike makers toyota, honda, ferrari, M. Benz, yamaha, kawasaki, suzuki, bmw, etc don't use turbo in their sport cars/bikes. Some sport bikes can rev over 10,000 rpm and turbocharging is still not used.

There is no replacement for displacment.

**wickeddrop** · 10-11-2003, 12:09 PM

Before you do anything, I would read this first

http://auto.howstuffworks.com/turbo.htm

I come from about 10 years of turbocharge imports. I used to have a mr2 turbo with every turbo upgrade you can think of, ran a 12.1 1/4 mile, my brother used to have a 97 accord with a turbo added to a 2.2l prelude vtec engine. If you are looking to turbocharge your 2004 civic, My suggestion to you would be to pass as you will be spedning a lot of money to make it right and it will put a lot of stress on your engine. A better suggestion would be th supercharger as it is a lot safer and no lag like a turbo.

Bottom line is be prepared to shell out some major $$$, b/c it doesnt stop at just adding a turbocharger, it starts that way and then you need gauges to monitor your engine, fuel management if needed, you'll want to turn up the boost after you get a small taste, etc, etc....I can go on for pages and pages.

**ttktom** · 10-11-2003, 12:49 PM

My Dad's Car Is Turbo Diesel the Turbo kicks in at about 2,300 rpm below that it's a slug as it only has 90 BHP about 4,000 RPM it has a slight flat spot. why don't u get it superchipped it costs about $350 Usd and gives u More Bhp

if i put it in my dads car it would give it from 90 BHP to 125 BHP.

**cooler** · 10-11-2003, 03:20 PM

Originally posted by Pete LSD
Well, I prefer fat torque versus very high revving engine .

then turbocharging is not the way to go.

**Pete LSD** · 10-11-2003, 03:56 PM

I am surprised that your dad didn't get a 150 hp, 2.0 Liter, turbo diesel car. The torque is incredible at over 200 lb ft. Second generation diesel is very popular in Europe owing to the fact that very low sulphur diesel is available there. Just imagine that with one 50 liter tank of diesel, one can drive from Vancouver to Calgary nonstop. BTW, we, the unlucky North American, is still stuck with the 90 hp turbo diesel from VW.

Originally posted by ttktom
My Dad's Car Is Turbo Diesel the Turbo kicks in at about 2,300 rpm below that it's a slug as it only has 90 BHP about 4,000 RPM it has a slight flat spot. why don't u get it superchipped it costs about $350 Usd and gives u More Bhp

if i put it in my dads car it would give it from 90 BHP to 125 BHP.

**Pete LSD** · 10-11-2003, 04:01 PM

I understand what you are saying but I am not looking for incredible output. Extremely fat mid range torque is what I am looking for.

Originally posted by wickeddrop
Before you do anything, I would read this first

http://auto.howstuffworks.com/turbo.htm

I come from about 10 years of turbocharge imports. I used to have a mr2 turbo with every turbo upgrade you can think of, ran a 12.1 1/4 mile, my brother used to have a 97 accord with a turbo added to a 2.2l prelude vtec engine. If you are looking to turbocharge your 2004 civic, My suggestion to you would be to pass as you will be spedning a lot of money to make it right and it will put a lot of stress on your engine. A better suggestion would be th supercharger as it is a lot safer and no lag like a turbo.

Bottom line is be prepared to shell out some major $$$, b/c it doesnt stop at just adding a turbocharger, it starts that way and then you need gauges to monitor your engine, fuel management if needed, you'll want to turn up the boost after you get a small taste, etc, etc....I can go on for pages and pages.

**Pete LSD** · 10-11-2003, 04:06 PM

Yes, turbo charging adds lots of complexity and expense. I am simply exploring this idea with the help of inputs from our car crazed BF'ers

.

Rick really summed up what I am looking for. VW, Audi, Volvo & Saab use low and mid pressure turbo chargers to increase output as well as torque. Maybe I should simply get a VW 1.8T to save the trouble of conversion!!!

Peter

Originally posted by cooler
then turbocharging is not the way to go.