shaheed

anyone got any k27/8 dyno charts for our cars?

Perry 951

I should have a few in another month or two.. once my motor is fully broken in. Not that it does you any good now...

Depending on the specific setup, the K27/8 will have enough flow at 18-20psi to produce 300-350rwhp, 320-380 tq. What you are running with the turbo, and how you have it tuned, makes a big difference in final power outputs.

87Porsche951

Heres a link to a dyno run from a 86 944 Turbo with K27/8 turbo.

http://www.geocities.com/sl951/dyno_...ott_story.html

I am also gonna throw in my two cents and to say that you porbably wont notice much of a performan increase with a K27/8 on a stock motor. Because the air intake wont match. Now if you put a K27/8 on a motor with MAF Kit, Head Work, & Intake Manifold it will match better and you will see alot more power and less lag. K27/8 on stock motor will have alot of lag. If you plan on just upgrading turbo and not anything else then your better off with a K26/7 hybrid to replace the stock K26/6. The K26/7 will spool just as fast (sometimes faster) than the K26/6 and offer more top end boost. Also will match your motor better.

Also if you do get the K27/8 dont plan on running the turbo's full boost potential without more fuel and air or you will get detonation and destroy your motor.

If I were you I would focus on a head & intake first then upgrade to MAF then get a turbo.

Good Luck!

adrial

87Porsche951,

I think you've got it backwards. You want to do MAF and big turbo, then for those last few precious HP...do headwork, etc. Look at the few people that have an upgraded intake manifold...that means something.

What's a k26/7? Do you mean a k27/6?

A MAF/MAP kit typically goes right along with a turbo upgrade. It is the easiest way to get a correctly sized intake pipe (stock intake boot will be way too small) and give you the ability to tune the amount of fuel going into the engine.

Dont have any dyno charts of 27/8's , though.

87Porsche951

Actually if you ask tuners they will say that head work should be one of the first performance mods to your engine because it doesnt matter how much boost your running you still have to flow them through the head for them to reach the combustion chamber. A good intake manifold is key also to flow more air into the head and combustion chamber.

Your correct about getting the turbo and MAF together.

Most people who get Intake Manifold dont upgrade anything else. Its useless to have a intake manifold that flows big numbers if your head cant.

You need your Intake Manifold and head to flow good numbers to have optimized flow and fuel mixture.

But with Hi Flow Head, intake manifold, turbo and MAF you will be running some great numbers. When upgrading turbo dont forget to upgrade your Wastgate & Diverter Valve also.

Another good tip when doing high HP & TQ mods to a motor is have the motor rebuilt with new and heavy duty parts. So, your motor can handle the extra strain and have reliable power. Go with Mahle pistons and bigger cam to flow even more air.

Ski

I don't know which tuners your talking to but in my brief experience not one mentioned head first. It was mentioned in conjunction with my turbo, intercooler, intake upgrade, etc,,,but not first.

The 951 head is actually quite good - yes it can be improved on the intake side, as the exhaust is in good shape already and should only be messed with if you know what you are doing as not to harm the ceramic lining. The MAF/MAP + turbo combination, along with proper fuel and software will get you the best bang for your buck to start, well my .02 anyway, as I agree with adrial. Also look at some tuner packages. Not one mentions the head in those packages. The head and the intake will get you the last 20-30hp that you may be looking for.

Skip Wolfe

87Porsche951

I'm thinking that you are thinking of normally aspirated engines. Almost all NA engine benefit from improved breathing which is why all intakes are such a popular mods for the Japanese imports. Turbos on the other hand have the crutch of forced induction to overcome restrictions. Yes there are some restrictions in the 951 head and manifold but they really are not that big of an issue unless you pushing lots of air - much more than a k27/8. The 951 head is pretty good right out of the box as Ski stated and really the only big thing I've heard about the intake manifold is that the flow is totally balanced. I agree with Adrial and Ski that head work should be aways down the list and intake manifold should be reserved for those going for 400+ hp. There are really quite a few other items that will give one a much bigger bang for the buck with a MAF or MAP piggyback or standalone fuel controller being the most important.

shaheed

i do have a MAF already, the car was making 267/320 at the wheels with MAF and k26/6, but the k26 was clearly running out of steam at high rpms and recently it started smoking.

what i really wanted to was pick up the vitesse stage one kit, but my better half has been bitching at me because of how much money i'm spending on the car and i found a k27/8 cheap.

i realize that i'm going to increase lag by going with the k27, which is a shame because one of the things that i really liked about my current setup is that it spooled really quickly. ideally i'd like to get an idea of what kind of power i can make at 15/16 psi.

fast951

Shaheed,

The best I could do with a K27#8 was around 330rwhp. 15-16psi my guess will be around 270-300rwhp... I'm looking for the dyno charts with my K27#8 from years back, will post them if/when I find them.

Danno

"Actually if you ask tuners they will say that head work should be one of the first performance mods to your engine because it doesnt matter how much boost your running you still have to flow them through the head for them to reach the combustion chamber. A good intake manifold is key also to flow more air into the head and combustion chamber. "

Yes, port & polish with other head mods will make a difference in black & white, all-or-nothing, qualitative terms. BUT... you have to quantify that statement with numbers. In terms of actual performance gains for dollars spent, it is one of the lowest bang-for-the-buck values out there. Let's say that's all you did on a stock car, $750-1500 on a P&P prepped head, +$1000 labor to install. What will you get in the end? About 10-20hp increase over stock maximum!!! For that same price, you might as well get 106mm pistons and bore & sleeve the block for a larger 50hp increase. As an initial upgrade on a stock car, you can't beat our GURU Racing Chip Upgrade for a +50hp increase for only $290 !

Now, let's say you've already done a turbo upgrade with MAP/MAF for about $2500-3000, that's a good deal for a +100-150hp increase over stock. THEN the next step may be a P&P head. This next $2500 will then get you another 30-40hp. It all comes down to HP-gained per dollar spent.

Here's a dyno-chart of Paul's car with K27/6 vs. K27/8 (both @ 18psi boost):

Velvet951

I'll have one to post on Monday comparing my k27 with autothority chips vs Guru chips. It'll be interesting to see the a/f improvement I get with teh guru!

toddk911

My friend here in town with K27/6 and Steve R chips, test pipe, injestors and weak wastegate, only held 13 psi, laid down 255/265 to the wheels, hp/tq respectively.

With stock motor and stock AFM!!!

87Porsche951

The stock intake manifold is unbalanced and will run lean in one area and rich in the other. There is really no way to fix that problem even if you get the intake manifold honed. Thats why I say get a new Hi Flow intake manifold. Some of you might not think that spending all that cash on a Hi FLow head is worth it but those extra air flow is not just for power increase. The motor will run better, idle smoother. You will se a increase in throttle response, the turbo will spool faster and wont have to work as hard to force air into the smalller ports. Plus you can actually tune the motor correctly and not have to worry about running one piston lean and the other rich while the others are fine. I disagree with the statement that it should be reserved for cars running 400+hp because all cars would benefit from a motor that would be able to be tuned correctly and not a motor you really cant tuned to its full potential because of an imbalance.

If your planning on doing all these mods then I guess it doesnt matter which way you go as long as its done correctly and the motor is still reliable.

And another thing is that alot of people say you cant run 400+ hp reliably and thats BS. A Porsche motor can make well over 400 reliable hp if the motor is actually built to support that much power. Alot of ricers just slap a huge turbo to up there 80bhp honda in power.

Wormhole

I’ve heard and listened to this point before and I think we need to think in more global terms when thinking about airflow at certain points. Porsche designed the intake manifold and flowed each runner considering and taking into account the breathing characteristics of the WHOLE assembly, not just the manifold. This is where Porsche is light years ahead of the competition; they spend tons of R&D dollars tuning the frequency pitches for optimal performance. It’s unfair to assume uneven intake runners will result in uneven fuel mixtures. Look at the intake manifold on the 959 supercar, it’s even more unbalanced then ours, surely this is no accident……

blitz951

This doesnt answer the thread question but I think 87porsche951's point about the head is well taken because I have been in many 951's with K27's and while there is a difference from stock it is dramatic when the head is done right. I think the head is critical and I am not sure many 951 tuners know how to improve on the design so there isnt much said about how important it is. My friend on the other hand had radical head work done by a guy who does heads for drag cars and the car pulls like a raped ape at 15 psi compared to what other 951's do with no less than 18 psi. This is a buddy of mine and Danno has driven his car and if he is on line he can give the details on the head as I am no expert. As far as the intake I do agree that porsche makes things with alot of research behind them but if the car is modified with head work or the power band is shifted higher, etc. then I would think that the stock intake would not give the best performance compared to what is out today but I dont have first hand experience with this so maybe someone who has a different inake can give us there opinion.