4g61t.org

I posted this once but it's deleted, I can't find it anywhere.

I put my Colt on the dyno recently and I'm just looking to see if there is any room for improvement. Here are the specs: 1.6L with Wiseco 10:1 pistons, 1.8L head (small combustion chamber with 1g 2.0L size runners), HKS 264/272 cams, 2.0L intake & TB, 2.5" ic pipes, Supra smic, small 16g, 1000cc hi-Z injs, walbro 255, 3" downpipe, no cat and 2.5" full exhaust, Link V3 on speed density with/dual maps for E85 and 92oct. I think that's about it.

I'm wondering if it's common for the little 1.6 to have the peak torque so high of rpm. Then engine has always been laggy even with the small 16g, you can see it doesn't reach full boost until close to 4000. I don't know if all 4g61s are so lacking of torque down low like mine. One other thought is the clutch, it's only a 215mm Exedy OEM replacement so I'm wondering if some of the waviness of the power isn't the clutch slipping. Thanks for any input.

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'89 Colt GT w/bigger than stock turbo
'91 Talon AWD w/bigger than stock turbo
'05 Dodge diesel w/bigger than stock turbo

I replied on NABR. I will track down the dyno sheet as soon as I can. I only have one with the HX52. And of course that will be laggy.

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1985 Mitsubishi Cordia
Build in progress

Well, considering they're not stock cams, I'm going to say yes, lol.

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Early 2000's: 1992 Summit sedan - 14.1 @ 100.9mph w/ 155/80 13s
2012: 1989 Dodge Colt GT Turbo - 14.9 @ 100mph, 10psi/s16G

Yes, it's common. These engines are not torque monsters. It's an extremely short stroke and a long rod, which is going to be oriented toward more high-RPM power. Even the 2.0's aren't incredibly torquey. My 2.0 doesn't make peak torque until after 5,000rpm, but of course everything in my setup is built around top-end power.

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

I'm more familiar with the 4g63 for sure. I knew the 4g61 wasn't going to be a torque monster but I guess I figured it would have a similar power curve as its 2.0L brother, just lower power for the same mods. I know one thing I switched at the same time as installing the injectors and tuning for E85 was installing the F5M33 tranny. The taller gears definitely suck for driveability on a low torque engine.

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'89 Colt GT w/bigger than stock turbo
'91 Talon AWD w/bigger than stock turbo
'05 Dodge diesel w/bigger than stock turbo

I've read when some guys have gained a little mid range torque using a Cyclone intake manifold controlled by ECM Link. Has anyone here done this? Anyone think it would be worth running that setup in my situation?

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'89 Colt GT w/bigger than stock turbo
'91 Talon AWD w/bigger than stock turbo
'05 Dodge diesel w/bigger than stock turbo

I think a Cyclone manifold may help you, especially if it has the narrower runners to match the 4G61 head ports.

Did you do anything to address where the large 2.0 runners meet the small runners of the 1.6 head?

EDIT: Nevermind, I scrolled my screen to the side and saw that you have the 1.8 head. Still, the cyclone may help.

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"A good day racing is better than a great day fishing!"

^^^ I wanted to say the same thing.

I suspect 240 ft/lbs (if I read the graph correctly), is pushing a stock clutch, especially 215mm of flywheel contact area and a full face clutch.

I also think the Cyclone can only benefit torque, and considering the 4g61t stroke benefits higher RPM, you need whatever you can to counter that for torque production; ie articial displacement (cfm,boost) and runner design.

If stock 4g63t's see 20-40 ft/lbs of extra torque from the Cyclone, how could it not benefit the 4g61t?

USDM C53A 4g61T AC compressor will fit with the JDM Cyclone rear support bracket, you just have to grind off a small portion where it will contact the AC compressor housing. Everything else should fit properly.

Edited to reflect the fact that I have now got the proper info on Cyclone manifolds and 2.0L engines, swapped into a C53A that has the original AC system..

I have tried three times since you posted this up to go and grab a dyno sheet. With the holidays the place I dynoed the 1.6L has been in and out a bunch. I am going to try again monday for you.

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1985 Mitsubishi Cordia
Build in progress

Everything is set up for huge airflow...except your turbo.

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Had a:
1991 Eagle Summit ES Hatchback - 4g15 12v 5spd
1991 Dodge Colt -4g15 12v 4spd
Have a:
1978 Oldsmobile Cutlass - 468BBO TH350
Round 3:
1990 Dodge Colt-4G63T 5spd

^Bam!

Everything looks pretty normal to me, turbo will be the game changer here.

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89 Mirage Billet 20g 63t 12.4@120 417whp 400wtq @ English Racing.
89 Colt GT E316g
06 Silverado SS
07 ZX6R

Well, I have to resist the erg to go wild with the car. I have an AWD Talon racecar for that purpose. Its hard to resist but I must keep the Colt as a great daily driver that gets great economy. I was only thinking if maybe I could gain a little more torque for cheap yet not hurt power or fuel mileage, might be worth a shot.

Some of you guys with bigger turbos on a 1.6, do you think I could put on say a 20g or even an FP Green and NOT lose any economy? It would obviously move the power curve up and probably not make boost until 5000 or even higher.

I'm currently getting 40mpg and I just don't want to turn it into another hot rod that gets 30mpg. I drive 100mi a day and WA has some of the highest fuel in the nation. I spend $600/mo on fuel as it is. Keeping the Colt an economy car is a must.

What would you guys do? Go bigger turbo or leave well enough alone? Thanks.

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'89 Colt GT w/bigger than stock turbo
'91 Talon AWD w/bigger than stock turbo
'05 Dodge diesel w/bigger than stock turbo

I remember seeing guys posting (pre-Link days) that they were getting 30+ MPG with larger turbos that were staying out of boost at light cruise highway speeds, and that they were able to lean out a bit. If you are getting 40MPG already, I don't know if you could get it any higher than that. You are way ahead of the game.
If less CFM was pushed into the motor, less fuel would be required assuming same engine RPM via larger turbo charger setup.

Kinda cool you have a higher horsepower output per cubic litre than most members here, and get the highest MPG out of all the members that I have seen posting.

I'm liking those number on pretty much a s16g setup with all supporting mods.. ill be having the same setup on my 89 gt 4g61t, minus cams. So ill be happy breaking 200hp good job there bud!

Plan on taking this thing to the track this year? PR?

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89 Mirage Billet 20g 63t 12.4@120 417whp 400wtq @ English Racing.
89 Colt GT E316g
06 Silverado SS
07 ZX6R