DanaT

Hey all,

I have had my 951 for quite a while it does fine making power with a K27-6. Like most similiar 951s, it is around 300rwhp.

I just bought a car that is stock for a different reason. I bought a 2nd generation Eclipse GSX. I need a stock vehicle to ship Europe that could be driven in all weather (rain, snow, etc) and that would pass an inspection (too many mods on the 951 to ship).

Seeing what people are doing with these little engines (2.0L) is amazing. It seems to make 400-500whp isn't all that hard and they do it with small turbos. (the littel t25 turbo comes on really fast in the eclipse and almost doesn’t feel turbocharged). Looking at the 16G turbo it flows 505cfm at 15psi. Typically these turbos are claimed to make around 370hp.
Borg/Warner claims the K27 turbo http://www.turbos.bwauto.com/product...lVehicles.aspx flows 0.38kg/sec (680CFM) and output range is up to 330kw. 330kw is 443hp.

Putting the numbers in perspective 505CFM / 680 CFM = 0.74. Using the 370hp number and dividing by the 0.74 that is about 500hp. This means that the K27 should be able to output around the 440-500hp range.

So why does the 951 make so little power running a K27? I would expect that a K27 would put putting down around 380rwhp. It doesn’t seem that anyone really makes 380rwhp with a K27 on a 951 engine. Is the 951 engine just inefficient or the 4G63 engine just that great at making power? With 25% less displacement, I would think that the pressure (and flow) would have to be 25% higher for that little engine to make power.

Also, I realize that the DSM are AWD and launch like crazy, but the trap speeds are easily seen in the 125mph range in the ¼ mile. The 951s making decent power are no-where near this.

So what makes the 951 at such a disadvantage power-wise?

Just as a side note, the current rage in the DSM world is a Holset HX35 turbo. They are claimed to spool up like crazy and still support 500-600. Even better is they are $100 junk yard turbos off of dodge Cummins trucks.
-Dana

Josh B

Actually I would be surprised if your K27-6 was making even 300 rwhp unless you are running on race fuel and even then it would be a stretch. What sort of wastegate do you have on the car?

On my car with a tial 38mm, Vitesse MAF/chips, 55lb injectors, 60-1 hifi turbo and a lightlly worked head I put down 293 rwhp on 93 octane at 17lbs boost. Granted I probably have some room for improvement on my A/f ratios but I don't think I'll be pulling another 50hp out of that....

All I can figure is that these other cars have higher efficency heads, tighter engines and fuel maps leaned out to within an inch of their block's life.

Dougs951

Well those engines do have 4 valves per cylinder and are DOHC so that cant hurt. The engine in the turbo eclipse's are the same as the Evo from the same time period.

INURGRL951

I noticed that alot of other engine seam to make alot more power easier then a 951 but in the end they are still slow, there are exceptions tho. The displacement of the motor being 2.0 vs. 2.5 makes it not needing to have a turbo as big as the 951 to erect the power the bigger displacement engine need a bigger turbo to do more.

I also think that there is alot of people that are afraid to "try " things on a 951 thats why alot of them kinda hit a wall at about 300-320hp.

costas

DanaT

Yes. I believe there is some truth to people are afraid to try things. When a 951 lets go, it is expensive compared to other engines. Also, there just isnt the number of people doing it to help out.

As to the smaller engine needing a smaller turbo to extract power, I dont believe that arguement. Why, a given mass of air burns a give mass of gasoline and gasoline has a given energy content. Theirfor, to make 400hp on a 1 liter engine takes as much gasoline it does to make a the power as a big block chevy.

You can take some VE into account, but I dont think that VE is 50% different between engines.

I just dont see 4V per cylinder making that much of a difference, but maybe it does.

I also wouldnt say that other car that are easier to get power out of are slow. I think other than handling and top speed, the 951 is slow for their power and weight. Some of this I am convinced has to do with gearing but I think part is the older engine management that doesnt allow for agressive timing off boost and in general early 1980s computer technology. 10 years newer ECU can make a difference.

-Dana

95ONE

Motors are more efficient. But I think if you Slap your 951 turbo on your eclipse, you'd still max out at 300to the wheels. Won't know until you do it though.

333pg333

The increased VE of the later designed 16v tc would definitely help plus they would rev out to a pretty high rpm I'm guessing. The other thing to think of is that in that world of small capacity modified Japanese motors, the dyno number is THE most important thing to a lot of these guys. As we know you can make a dyno read just about anything. In Australia where the Jap scene is the biggest of our aftermarkets, they go along to a dyno and the guy asks "Do you want it in Shootout Mode"? Then he does whatever he does to give the biggest reading possible. While I agree that our 8v motors are old school and many of us think that 20psi is high, get these guys on a track with their buzboxes and see how well they go. Not to say that they'd all fall in a hole, but our strong suit is from a roll or on the circuit.

TurboTommy

Things to possibly consider to put things into perspective:

This statement: "It seems to make 400-500whp isn't all that hard and they do it with small turbos."
Hmmm, be carefull of exageration out there.
To get 450 whp (let's say 525 at the crank) you'd need a turbo compressor to be able to flow a good 700 cfm (at a little higher than sea level elevation, probably closer to 800 cfm). That's not a "small turbo" and to make that kind of power on 2 liters of displacement, you'd need some serious boost, even with DOHC. So, I wouldn't qualify that as "isn't all that hard".

I'm not sure how you get the conversion from .38kg/sec to be 680 cfm, but I vaguely remember getting some info that our k27, as we know it (there are slightly different versions) have a flow capacity of about 550-600 cfm. Also, looking at the chart on the bwarner site, the upper power levels of 330 kw is achieved with the k29 (if ya look at it again). So, this would correspond with a more reallistic power limit, of the k27, to be about 400 crank hp (maybe a bit more at sea level)

So, this is what your compressor is CAPABLE of; it doesn't mean you're making that power. The combination of the engine displacement, volumetric efficiency, and the boost you're running doesn't allow for the full cfm to flow through the compressor.
By the way, the #6 hothousing seriously comprimizes the VE.

blown 944

the heads flow over 350 cfm vs ~ 200 on most 8v. They also rev out much further using the larger turbo better.

It does still come down to the turbo IMO and it seems the choices have been very limited int he 951 street world.

How many 951 are running Holsets??.... 2

how many Borg warners?? 1 maybe??

Hell I bet there are few that are even running over a gt30 size (not that that is a bad thing)

How many are using anti lag to get it spooled up?? 0??

Too many variables to do a decent comparo

don't be fooled though just because they are after big dyno numbers. Many actually do make big power. Just look at the quarter traps...128plus in a 3000 plus pound car, is power however you look at it.

Rogue_Ant

As Sid said, the 4G63 head flows much better then our 8v ones. The DOHC design is also a better combustion chamber, helps prevent knock. Furthermore the spark-plug placement is ideal for proper flame propagation. Not to even mention the complete roller valve-train that is quite capable of fairly high rpm (~9000) with just up-rated valve springs.
They also have a few good engine management options available without changing any wiring. Compared to the normal 'mail-order' tunes of the Porsche world.

The 951 world is afraid of boost. At least compared to the 4G63 world. Stock Evos run ~19psi from factory, and it is quite common to see DSMs/Evos running in the mid-20 to low 30psi of boost.

A K27 should make 300rwhp, unless you are running ridiculously low boost.
Josh B, either your dyno reads really low or something isn't healthy with your engine... you definitely should be making more power then that.


-Rogue

INURGRL951

Hey Sid I guess I get in the "other" category because im running a GT35R turbo and I run 33psi of boost. I haven't keep it up there all the time for the simple reason of the mixing of gas I got to do and the tires wont stay grounded !!


costas

333pg333

What numbers are you getting at those boost levels costas?

86951Turbo

DOHC 16V is a great advantage

Higher Revs help; especially the high revving honda engines. Although, watching FWD cars trying to get traction is another story.

Finally, OTS engine management options for the hobbyist is further along. What I noticed when I first got the 951 was the lack of options, or flexibility of the programs; from turn **** piggybacks and ridiculously priced MAF conversions. Seriously, $1000+ MAF conversions + purchase of a piggy back,there are full standalone ECM's for that price, to plug and play chips to a 'similar' setup. Really? It was really frustrating when coming from Hondata and AEM to the options in this community. Although, the AEM FIC with the onboard 3 bar map sensor might fit the bill. Really, you can have nice, expensive, and shiny parts on your car, but without proper engine management all your left with is the inevitable Ricer bitterness.

Sorry for the rant.

86951Turbo

Forgot one thing, though.

These cars are not drag strip trailer queens. They are track cars where peak power doesn't really matter; especially in spec classes.

DanaT

Sid, are you one of them running a holset?

I guess when I say it is "easy" to make the big power, how about "cheap"? Turbos are cheap compared to 951 turbos. Everything is simply cheap ("cheap" is relative).

Yes, I agree that the 951 has many things the eclipse doesnt have. Some of benifits of the 951 is simple feel. But even mid range on my 951 doesnt feel as strong mid range as the eclipse. The stock eclipse turbo hits 15psi boost really quick. it will hit that well before 3000rpm in 1st gear. My 951 doesnt hit that boost until of 1st gear.

I agree that the k27/6 needs more exhaust. Maybe after 12 years on the same turbo, I need to "upgrade". Most things on my 951 are "old school" as it was done in 1997. There wasn't much available then. I have upgraded some things powerwise since then (basically a nice BOV, wastegate, and boost controller). But really, it is limited by chips (1997 Authority MAF) and engine management. A faster spooling turbo that flowed nice would be good.

Problem is, that I only drive the 951 in the summer. I kind of forget about the car during the winter and then want more power in the summer. Then I don't have time to work on it because I want to drive it.

Maybe I need to just pay Sid to make my car run fast.

-Dana