okay, my car is going to the shop this week for my twin turbo/shortblock build. I had the vortech on for about a year, got bored with the power and now finally decided to go twin turbo. Here is the parts i will be installing

-Greddy 18g twin turbo kit with greddy intercooler
-550 DW injectors on the car (will be upgrading to 800)
-AAm fuel basic fuel return
-Kinetix SSV intake manfiold
-currently running utec
-test pipes

as far as my shortblock build i havent ordered the parts yet, i was going to take it to a machine shop first so they can tell me the bore i need for my pistons. My goal is 550 whp but hoping to upgrade to 650ish in the future.
the parts i plan on ordering
-eagle rods
-wiseco pistons
-cosworth headgasket
-cosworth bearings
-ARP main studs

anything else i am missing from my shortblock build?? what bore do you guys recommend me to get for my pistons?? there are like 4 different sizes for pistons and headgasket.. not sure which one i want... any input would be great.

 

Change that GReddy kit to a GTM kit.

 

going for 650hp, look into upgrading ems.

 

Why? You don't know which kit will be better for the OP unless you know more about his goals with the car. If he is going to be road racing the car, he should use water-cooled turbos and cast iron exhaust manifolds, so the GTM kit is a good kit (that's what I now have). The JWT and APS kits also are worth considering (if you get an APS kit, try to find an older one with Garrett turbos).

If he will be using the car for street or 1/4 mi. use, the Greddy is a great kit. The Greddy kit now is a little pricey, but some people have been finding really good bargains on them lately. Sound Performance and Speed Force Racing also make good turbo kits. These do use water-cooled turbos, but should only be used for 1/4 mi. and street use because they have stainless steel exhaust manifolds (the types of manifolds tend to start sagging due to heat when used in road racing).

Of all the kits, the APS kit is probably has the best fit, followed by the Greddy kit. If the OP will be doing his own installation, this is important.

In summary, the turbo kit that is best for one person may not be the best turbo kit for everyone. It all comes down to an individual's goals with his particular build. I started with a Greddy kit and it was an outstanding turbo kit. Then I decided I wanted to get into road racing, and that is when I sold the Greddy kit and bought a GTM kit. Had I never decided to road race my car, I would still have my Greddy kit today.


OP, compare the performance of the Kinetix intake to the 5/16" plenum spacers before making your final decision on that.

 

change the utec plz plz

its realy realy bad for high power

 

well only BB turbos from SFR or SP are water cooled. Journal bearings are more than fine for normal driving or drag racing.

But ya, you dont get bolt on ease with any kit other than the APS or Greddy.

 

+1 and reliability, i have been running it for less than a year and never more than 12 maybe 13psi and it's leaking already.
@ 650hp you will see a lot more boost so SSV probably not the best of choices.

I run both SSV and Utec which were perfect supercharged but I won't recommend it to anyone having higher power goals.

 

^^^^

When I started round 1 of my build about a year and a half ago, I compared the Motordyne 5/16" plenum spacer to the Kinetix intake manifold (it was eigher the SSV or an earlier version of this). Specifically, I found different dyno plots that compared these to the stock plenum. The 5/16" plenum spacer increased hp/torque almost all the way accross the rpm range. The Kinetix manifold, however, gave up quite a bit of mid-rpm torque/rpm for marginal gains in the upper rpm band. Based on the dyno plots that I saw, the 5/16" plenum spacer was the all around better choice for my goals. If someone is building a dyno queen and are only concerned about the peak hp number, then the Kinetix SSV will be OK. Of course, that was a while ago and Kinetix may have improved their manifold since then, so it may be worth doing some further investigation on this. Nonetheless, the air volume in the plenum portion still is fairly small, which will adversely affect mid-rpm torque. Also, I have not looked into the Kinetix Racing V plenum, so that might be worth looking at as well. From the structure (and the price), it looks to me like it may be a better all around option if someone really wants to stick with Kinetix.

 

with the gains that SGash made by lifting his plenum off the manifold (like 20+hp), i wonder why no one has made a 1" or bigger spacer.

I'm almost tempted to try 2 stacked MD spacers.

 

Although he gained peak hp, he probably gave up hp in the mid-rpm band. You can see this by comparing the dynos on the 5/16" spacer to the 3/8" and 1/2" spacers. The 5/16" spacer provides, imo, the best torque curve accross the rpm range.

Remember, when someone posts their peak hp, they are only telling you what they achieved at that specific rpm, and there is no indication of performance at other rpms. If you are building for overall performance, you are looking to increase the total area under the torque/hp curve in the entire rpm band that you will be operating at, not just the peak hp. If you are building just to acheive peak hp, and don't care much about mid-rpm performance, then a larger spacer might make sense.

Much comes down to how the car will be used. For street use, a fat torque curve is nice to have. For those cars that are only going to be used on the track, you want to put the focus on the rpms at the shift points. For example, if you have a 6MT, and shift out of second at 7500 rpm, your rpms will drop to around 5200 rpm when moving into 3rd gear. Here, you want to maximize torque/hp from 5200 rpm to 7500 rpm, and the 1/2" spacer might be a better choice than the 5/16" spacer. But most of us do not drive like this all of the time on the street, so it is nice to increase the torque in the lower rpms as well, so the 5/16" spacer might make more sense.

Check out the plenum and spacer comparisons in post # 6 of this link:

https://my350z.com/forum/intake-exha...rd-plenum.html

It compares various plenum spacers to the Kinteix V4 and Crawford plenums. The 3/8" plenum spacer outperforms the 1/2" plenum spacer up to about 5000 rpm. The 1/2" spacer pulls ahead from about 5000 rpm to 6200 rpm, then they are neck and neck. Here is one interesting comment from Hydrazine:

"When the MD spacers were in development a 3/4", 1/2", 3/8", 5/16" and 1/4" spacers were all tested and compared.

In all the testing it was found that the 3/4" spacer actually performed less than any of the other spacers. The peak was down and area under the curve was down. "

One last note, these were tested on a N/A build. There will be differences in a FI build, so it is probably worthwile for someone making the decision to do further research.

st8dum1, if you can get your hands on SGash's dyno plot, it would be interesting to compare his torque curve to those of motors using the 5/16" or 1/2" spacers.

 

I may be wrong here, but don't you choose a piston size first and then send them with the block so it can be machined to the individual piston after everything is weighed and balanced

I thought I remembered Jim Justice saying that is how my last block was done.

+1 on getting a better EMS, but that is just because I hated my utec so much. jtgli is making decent power on his 18g kit on a stock block and his car is very smooth with the utec.

The gasket issue has been covered several times in other threads, so I will just say I would reccomend HKS or the HR gaskets with L19 studs, but you need to decide prior to getting the block machined if you choose the HR gaskets, so a coolant passage can be cut.

Also, you may want to consider a pathfinder cooling mod and some heat wrapping on pipes or even better yet, get the manifolds and downpipes ceramic coated (or ceramic coat everything like Terry has done).

 

^^^

+1000

Very good information.

Also a note for the guys starting to piece the parts together for their builds. If someone makes a post just stating to use a particular component/kit without explaining why, take that recommendation with a huge grain of salt. The recommendation may be good, but all to often it is not. Every build is different and people have different goals. So what is best for one person is not necessarily best for everyone else. More often than not, people making such posts have not fully researched the subject, and just go by what is popular at the time or what they have in their car. But there are too many variables that come into play and the entire build should be cohesive, meaning that the components selected should work together to best achieve the owner's goals. There are not a "best" turbo kit, a "best" cam, a "best" intake plenum, a "best" clutch, etc., etc. There are components that work better than others at certain rpm ranges and hp levels, but even these come down to whether the car is going to be a street car, a 1/4 mi. car, a road course car, or a hybrid of any of these. I have selected my components for a hybrid street/road course car, but many of my parts I certainly would not recommend to someone who is building a drag car, a full on road course car, or a car that will exclusively be a daily driver. Also, cost is a big factor. I like my Cosworth plenum, but unless someone is looking to dress up their motor, it is not the best money spent for someone looking to max out around 550 whp. For the OP's goal of 650 whp, it might be worth looking into, but is not absolutely necessary.

 

I love how people say they can feel a difference. 10 hp at 6000+ rpms? LOL

That graph shows there are no differences in the midrange between ANY of the tested options, so how do you come up with the 5/16" is better? Those tiny separations are well with the noise of a dyno that will read 100- 1500 hp. Now if there was a N of 3 or more, maybe

better yet, those are all on a NA motor. At a minimum a bigger volumed intake mani would decrease boost pressure at the same power.

Just wondering bc Charles's manifold is almost 6L in volume. HUGE compared to stock and double spacers would be an easy way to gain more volume.

sorry for the OT

 

That is a fair point, the differences are small, but nonetheless it correlates with Hydrazine's own testing (the plots shown were performed by Nissan Sport Magazine). So, the results showed repeatability, which tends to indicate that the differences were real.

The 5/16" and 1/2" spacers are mostly within about 2.5% of one another (as far as I can tell from the graphs), but that is on a N/A build. On a FI build I would expect the value of the hp differences to increase, assuming the same percentage differences. Though 2.5% at 250 hp is about a 6 hp difference, 2.5% at 600 hp is about a 15 hp difference. That still is not huge, and it is a SWAG based on extrapolating the data, but if your going to select one over the other, why not select the one that gives you a little more in your operating rpm. You yourself said you were considering a 1" spacer to get 20 extra hp. Heck, you can get 20 hp swings merely by dynoing in different weather conditions.

How?

EDIT: Perhaps the greater volume provides more consistant pressure. With a smaller intake, there would be greater pressure fluctuations each time an intake valve opens and closes. So I see how a larger plenum may help to run slightly lower boost.

EDIT EDIT: Kinetix has a replacement for the SSV manifold, it is called the "Velocity Manifold." The plenum portion is pretty small. If the assumption is correct that the boost required to get a certain hp is relative to the size of the plenum, the new Velocity Manifold does not look like it will fair well. At the list price of $749.99, it might not be worth the money. If anyone has a comparison to this with other manifolds/intake plenums, please post.

I have not spoken with Charles about his manifold. Nonetheless, I'll speculate on why he wants a large plenum; the intake runners and the plenum work together to create a resonance. This resonance helps increase the velocity of the intake charge at a sub-harmonic of the resonant frequency (to tune the fundamental resonant frequency of the intake runners/plenum to the rpms of the motor would be better, but the runners would be loooonnnnggg).

Charles' intake runners are fairly short, for example in comparison to the Cosworth plenum. So, given the same intake plenum volume, the sub-harmonic of interest would occur at a higher frequency, and thus higher in the rpm band. By making the volume of the intake plenum larger, it lowers the resonant frequency of the system, and thus helps to compensate for the short runners. I don't know if you have ever played with tuning the ports on a sub-woofer box, but it is somewhat analygous. Given two sub-woofer boxes of different sizes, but that are to be tuned to the same resonant frequency, the larger box will enable you to use a shorter port. We hammered this subject to death about a month or two ago.

 

hey man good luck with the new build, for what it's worth I ran a UTEC on my last power setup of 560/590 and it ran fine. I was going to upgrade to the Haltech but decided to sell the car.

 

Where are you getting the work done? Sounds like fun... ;p

 

exactly. the pistons have to be sent with the block to be machined together. Piston sizes aren't exact so the machinist will match each bore to each piston individually.

If these are stock pistons then You have to go to the next size up which is a +.020" overbore. From there they machine the cylinders to exact sizes of each piston.

 

I agree with you and Cass UNLESS he had some cylinder wall damage then the machine shop would say you need to go at lease 20thou over to get the scoring out of the cylinder wall maybe thats the case or maybe not. I would decide what size pistons I wanted and then when its tore down ask the machine shop will i be able to run pistons that are 20thou over or do i need to go larger if the car is running fine I cant see it being an issue. In most cases 20thou is a safe bet.

 

very true if it's a blown motor

if it's a functional motor he should be fine. he can always just get 40 thousandths over to be safe. If something took the cylinder wall 40 thousandths out then the cylinders probably need to be bored and sleeved or replaced.