M20 low boost options

[Falconer]

So I've been mulling over the idea of boosting my m20 (has 207,000 kms or 128,000 miles) by slowly acquiring parts over the next year. I feel I have pretty realistic goals, but I'd to hear some feedback and suggestions.

Before I get interrogated as to why I don't just swap in the ubiquitous s42, and slap on 8 superchargers to get 40,000 extra hp and the ability to tow in a moderately sized cruiseliner, I'll explain the reasons for my wanting low-boost. It should help to define my goals.

This will be my first time boosting and thus a new frontier for me. It's less about the extra power, and more about the road getting there, learning and getting my hands dirty. I'll be happy with gains of 30rwhp, hopefully from 5-6 PSI. Hell, my stock m20 has kept me entertained for years now. This means I'd like the car and motor to remain as much stock as possible. From my reading, the stock Motronic (with the assistance of a wideband O2 sensor and higher pound injectors) can handle 5-6 PSI quite easily with no idling issues. I definitely want to avoid things like megasquirt for now. Keeping things like A/C, decent gas mileage under light driving conditions and low noise is important to me.

Reliability, Fast, Cheap. Pick two. Well I definitely want reliability, but 5-6 pounds of boost isn't too much so lets talk budget. Like I said, I'll be acquiring parts over the next year, hopefully patience will help me reduce cost. While I'm not wholly opposed to going to TCD or revshift and buying an $800 manifold, I'm wondering if that's overkill for the amount of boost I want to run. Are there mid-range alternatives?

I guess I'll end here and see if I'm out to lunch. If you need to grill me with more questions or chastise my expectations, feel free to do so. I'm here to learn.

[ak-]

If you intend to stick to low boost and Motronic (assuming you'll be using the AFM and a rising rate fuel pressure regulator), injector size is going to be your ticket to a good idle.
Yes, with the wideband you will be able to see adjustments from the AFM/fpr to get proper air fuel ratios, but the thing is your ECU ignores all adjustments on cold-start. So big injectors on the stock cold start map is going to give you a chugging rich idle.

For a proper idle you shouldn't really try to dabble with anything bigger than 30lb injectors.

No, you don't need a super duper manifold for YOUR expectations. Many of us are running eBay internal and external wastegated manifolds with HIGHER expectations and are just fine.
Yes, a twinscroll and/or equal length manifold is more efficient, but I'm just talking based off your conservative expectations of 30rwhp gain or more.

My opinion is ditch the AFM setup and go with Miller's WAR/MAF combo for the low boost conservative setup or go with WhodWho's plug and play Megasquirt setup if you intend to keep on tinkering with the car and possibly want to make more power (you will.)

Lucky that you have a motor that's barely broken in ;)

[TheTacoMan]

You will definitely need mega-squirt if you want stock reliability, and even 6 psi can be very fast if tuned correctly and having an overall efficient system. That means no holset turbos, I dont understand the need for putting diesel turbos on small inline sixes. They spool late. Keeping A/c with some of the manifolds is difficult. Gas mileage will suffer, I am consistently getting 20mpg at 15psi.
Also ebay manifolds work, Ive personally seen Six be put to use with no issues at all. Sure its not as efficient but when it is 1/10th of the price, and it can still can get decent numbers why bother with the 1000$+ manifolds?
Even at 5-6 psi 30 more whp should be so easily attainable if the system is built correctly. For example a holset turbo making full boost at 4500rpms at 10psi making 280whp(just an example), can be a good amount slower than another m20 making 240 whp at 6psi. Making a broad power band is key to having a fast car even at 6psi.

Read maximum boost by corky bell. Lots of information.

[saturnv7890]

Yup it's all about area under the curve, I just got back from the dyno. I've got a holset turbo with wayyy too big of an exhaust housing, it made 260 at 7 psi, but you can see the power doesn't come till late.

http://i.imgur.com/hawkToM.jpg

good for reliability and gas mileage though, as you don't see boost much while cruising because of the lag!

[Falconer]

If you intend to stick to low boost and Motronic (assuming you'll be using the AFM and a rising rate fuel pressure regulator), injector size is going to be your ticket to a good idle.
Yes, with the wideband you will be able to see adjustments from the AFM/fpr to get proper air fuel ratios, but the thing is your ECU ignores all adjustments on cold-start. So big injectors on the stock cold start map is going to give you a chugging rich idle.

For a proper idle you shouldn't really try to dabble with anything bigger than 30lb injectors.

No, you don't need a super duper manifold for YOUR expectations. Many of us are running eBay internal and external wastegated manifolds with HIGHER expectations and are just fine.
Yes, a twinscroll and/or equal length manifold is more efficient, but I'm just talking based off your conservative expectations of 30rwhp gain or more.

My opinion is ditch the AFM setup and go with Miller's WAR/MAF combo for the low boost conservative setup or go with WhodWho's plug and play Megasquirt setup if you intend to keep on tinkering with the car and possibly want to make more power (you will.)

Lucky that you have a motor that's barely broken in ;)

Thanks for insight. If you think the ebay manifolds are decent for this amount of boost, what do you think about the entire kit thats commonly offered? My distrust mainly lies with the compressor, is that warranted for 5-6 PSI?

You will definitely need mega-squirt if you want stock reliability, and even 6 psi can be very fast if tuned correctly and having an overall efficient system. That means no holset turbos, I dont understand the need for putting diesel turbos on small inline sixes. They spool late. Keeping A/c with some of the manifolds is difficult. Gas mileage will suffer, I am consistently getting 20mpg at 15psi.
Also ebay manifolds work, Ive personally seen Six be put to use with no issues at all. Sure its not as efficient but when it is 1/10th of the price, and it can still can get decent numbers why bother with the 1000$+ manifolds?
Even at 5-6 psi 30 more whp should be so easily attainable if the system is built correctly. For example a holset turbo making full boost at 4500rpms at 10psi making 280whp(just an example), can be a good amount slower than another m20 making 240 whp at 6psi. Making a broad power band is key to having a fast car even at 6psi.

Read maximum boost by corky bell. Lots of information.

Wouldn't a late spool be conducive to good (better) gas mileage while putting around town? As for making more than 30-40rwhp, my reluctance comes from the increase of stress on drivetrain and wear parts. Car will see a lot of daily duties for quite some time.

Yup it's all about area under the curve, I just got back from the dyno. I've got a holset turbo with wayyy too big of an exhaust housing, it made 260 at 7 psi, but you can see the power doesn't come till late.

http://i.imgur.com/hawkToM.jpg

good for reliability and gas mileage though, as you don't see boost much while cruising because of the lag!

Damn, that looks fun though!

[TheTacoMan]

Whats the fun of a turbo if you are not going to spool everywhere? :D

[ak-]

Thanks for insight. If you think the ebay manifolds are decent for this amount of boost, what do you think about the entire kit thats commonly offered? My distrust mainly lies with the compressor, is that warranted for 5-6 PSI?



Wouldn't a late spool be conducive to good (better) gas mileage while putting around town? As for making more than 30-40rwhp, my reluctance comes from the increase of stress on drivetrain and wear parts. Car will see a lot of daily duties for quite some time.



Damn, that looks fun though!

The only thing that I ever use from those kits offered is the manifold, maybe a few clamps/hoses, intercooler, and maybe the blow off valve.. since it's not really dangerous if it fails and makes a distinct sound if it does..
The charge pipes aren't tailored to fit.
The compressor is questionable.
A cheap wastegate that fails is dangerous if you don't notice it.
Feed line questionable, I wouldn't worry about a drain line.
Those manual boost controllers are garbage.
The catch can is useless and has small fittings.

A turbo'd engine will see relatively faster wear, but the variable is driving habits.. Daily driving my car, I'm in vacuum like 90% of the time and the only time I get into boost is when I'm trying to merge, pass a car, beat a yellow light or whatever.. and that's like sub 5psi only.

Assuming you drive like a normal law abiding person, lol, you could possible increase your gas mileage if your tuner leans out your mixture a little bit while driving in vacuum. This is off boost though obviously; boost = drinks gas.

[Kozworth]

Its definately possible to keep ac, but as a rule of thumb it seems much easier and more space deleting it. If you add a fmic, its pretty hard to have room for the fmic/oil cooler/condensor/radiator. Not to mention, there are a few ac lines that run right where the manifold would be.

I have a cx racing manifold. I would recommend it so far. There are a few adapters out there for <400