I posted this before, but it was off topic so I wanted to start a new thread:

It seems that the AEBS system would be the choice for me as far as engine rebuilding, but what I want to know is if the high cr 11.5 option was installed, would I be able to later add say a Vortech SC without changing down the cr or using race gas.

I don't have very deep pockets, so I wouldn't be able to buy the 8.5 AEBS system and f/i at the same time.

I would like to get the 11.5 system, and then later when I have the money, I wouldn't want to pay for swap out to 8.5cr, I would just rather have the Vortech with 11.5cr.

Is this wanting to have my cake and eat it too, or is it feasible?


The reason I like the idea of the 11.5cr AEBS kit and the Vortech together, is the low end torque provided by the higher compression engine would complement a centerfugial super charger if detonation would not be a problem.

Also, if I already had the AEBS 11.5cr kit, then I think that the addition of a Vortech SC would be more than enough for me power wise.

Also if I did swap out from 11.5cr to 8.5cr what kind of costs would that incur, and would I only be swapping the pistons?

Maybe 8.5cr pistons in combination with the AEBS kit would give me 9.5cr? I like the idea of a higher displacement higher compression ratio engine in our car. It seems to me that this would also retain the nature of the beast if you will.

 

why not just buy the Vortec kit and set it on a low psi,seeing you have a new engine that could take quite a beating for a while.FI would be a lot cheaper & less time consuming than rebuilding the engine.I also think you will be more satisfied with the results from the Vortec.I agree with sticking to a higher CR(maybe a little lower than stock), especially with centrifical SC's & turbos because of the potential lag.although lag hasn't been much of a prob for everyone.I just installed the Stillen SC and it's amazing.

 

If you want higher CR and boost, you need race gas. Without race gas, you get moderate CR and low boost or low CR and high boost. With boost, you up your effective CR even more when the mixture is compressed, so it will be even higher than the listed 11.5 or whatever static compression ratio. With the highest static I've ever seen on a stock car is the 11.7 on a GT3(I know there will be higher, but just haven't seen it yet ), I think you start to reach the limit of pump gas around 12. With boost on an 11.5, you're looking at effective ratios of much higher. I found this equation from NissanPerformanceMag.com

The effective compression ratio of a forced induction engine is (( boost psi / 14.7 ) + 1) * motor compression

So if you have 11.5:1 and want 6psi, that's 16.2:1, the 10.3:1 we have stock with 6 psi is 14.5:1. 14s:1 is much more manageable on pump gas.

Here's the article if you're interested. http://www.nissanperformancemag.com/may03/compression/

 

Thanks for the link, it seems boosting with the high cr AEBS kit would not work well. I was just thinking with the ecu reflash the kit could rev up to 8krpms supposably and high rpms would also compliment a centerfugial sc.

Maybe an 8lb tilton clutch would make up for the sluggishness of an ati/vortech kit using the AEBS modified to a cr of around 9.5.

I wish I had results from people who had already installed the AEBS kit with 11.5cr so I could judge just how much rwhp it puts out with typical intake/exaust mods.

Does anyone know someone who has been quoted a rwhp mark, or has already installed the kit and dyno'd thier car?

I would like to know how long the install takes also.

 

Engine building/modding is very expensive. So only plan on doing it once...unless you have an unlimted budget. Higher compression that stock is a definate no-no with F/I. But, there is some merit and data that would support a standard 10.3:1 forged motor with F/I. That way, once you get your motor back, it will have the same power characteristics as stock..but have the strength and fortitude to support F/I in the future.

Ideally, if you goal is F/I, a agree with the last poster....get the Vortech kit first, and enjoy it at a low and safe boost level...your motor will be fine. Then in the future, you can build the motor for more boost at maybe a 9.0:1 CR...or 8.5:1.

Good luck!

 

I dont want to seem like a A$$hole or anything however I dont see spending one dime on the stroker kit unless you are going for obscene amounts of power.

How much power do you want??

10 psi on a stock motor is making roughly 450rwhp which is 128.571 hp per liter.

4.3l x 128.571 = 552 whp as a rough estimate on 10 psi with the stroker. but we have never seen a dyno maybe this motor pulls strong up to its 7500-8000 rpms???
maybe you get 600 hp at like 10 psi??

right there that number 550whp is to high for the stock fuel system so there is more money there.

now we need a blower to make more boost. can you run the ati unit or vortec unit safely at say 13-15lbs?? who knows.

Well there are ati or vortec blowers capabale of over 25lbs boost so maybe need to custom fit one of those up!! Uh oh now we need some 1000 cc injectors or something who knows but the point is it it going to cost a fortune to find out.

I think the only reason to get this stroker kit for fi is to run like 800 whp on up and it will cost $$$$ tons.

Why not just build the existing motor for half the cost. 15 psi has produced 600 whp on a built 3.5l (greddy)however too dangerous with out a fuel system revamp.

point is how much hp do you want ????

how much are you willing to spend???

When you factor in the addiotional costs like tunning, em systems, clutches, labor, it becomes twice as expensive than most people think.

I say if you are fairly wealthy and want to smash 1000 hp then spend the $$$ on the stroker.

You want 500hp? 600 hp? 700 hp?

Take the money you would save over the aebs as it would buy you your F/I system, clutch, Solid LSD, and dinner for two!

Again im not trying to be A$$ to ya. It just doesnt make sense to me to spend the money on the stroker kit unless somebody wants to force feed it with 25-30 psi of boost and go nuts!

 

Squill, that is the whole point. Well, that and to pass a few supras.

 

I think most will concede that running a TT or SC setup at the "450rwhp level" day in and day out is "risky". A reasonable upgrade may be to simply correct the known weak link = rods. The rest of the OEM shortblock is then probably good to go reliability wise >450rwhp on 91pump and >500rwhp on 100 race. All the other internals such as crank, pistons , sleeves, studs etc are for extreme >600rwhp levels and those with lots of extra $$$ to burn.

 

Yea i get the point quite clearly however From what it sounds like what Jax350Z wants to do he should just build up the Vq block as it is and forget about the stroker.

Zxrage in your sig you state your goal as a 650hp daily driver.

Boulder nissans car hit 597 whp @ 14 psi with the greddy kit on top of a fully buit motor.

The fuel system is being upgraded right now as it just runs out of gas on that kind of power.

Whether or not you have the stroker you are going to have to upgrade the fuel system for that kind of power.

Once boulder nissan finishes the fuel system upgrade they will be able to turn the boost up to 22-23 psi which should be the max boost efficiency of the tdo5-18g turbos.

my prediction 700 whp but we will have to wait and see.

At any rate this would be with out the stroker which costs alot more than just building up the stock block.

I dont see the point of running the stroker unless A. you just want to have it because its a stroker and thats sweet! or B you want to try and make supras look silly!

Oh by the way APS turbo kit nice choice! Im waiting on that kit myself!

 

hmmm...

I do not have silly amounts of money, your opinions are apprecieated. The reason I ask of course is because I'm obviously not sure what route I want to take.

I will install headers/hf cats/catback exaust around the end of this month, and I already have a K&N drop in.

After those updates the only thing I would HAVE to have before getting say the Vortech kit installed is clutch/flywheel. I was thinking the tilton package due to the fast revving complimenting the Vortech sc.

Perhaps the best way to go is as GQ said, and to go ahead with the sc and then later maybe doing a little engine work to up the boost.

Everyones inputs are appreciated, I'm just trying to figure out what is the right route for me.
I am deffinetly not loaded enough to buy an AEBS and Vortech without a few years inbetween.

 

Jax, if your goal is serious HP, I would really suggest the TT over an SC. Problem with the SC is the difficulty of easily increasing the boost and tuning to the levels you are talking about.

I agree mostly with what Squill is saying. Build the stock block...and you can easily achieve 700whp and beyond.

If you think you'll do a TT, then skip the headers.

 

Yeah, I think I've decided to just upgrade to catback/HF cats & then tilton clutch. After that I will just enjoy my fast N/A Z for awhile whilest I save up the money for what will by then be better and more cost affective Turbo kits.

 

If you think that a TT or cent SC is your future plan , an intake Plenum (ie Crawford) is a good early NA upgrade that also serves the FI options well.

 

I second that! Factory plenum has terrible airflow problems throughout the cylinders which shows as much as 30% more air to the #5-6 cylinders vs the #1 and #2 cylinders causing tuning problems and tendency to run lean in the #5 and 6 cylinders even if the wideband shows good A/F ratios overall.

 

I like the Kenitix plenum, but I don't know if it's a good upgrade for FI.
What plenums work well with FI?

 

The Crawford has been used several times with FI >9psi with no issues so far.

For good measure I asked Crawford to add an extra seam welds on mine to assure high psi durablity. I was concerned with constant vaccum<->boost cycling stressing the welded joints.

 

Good god with 9psi still to go on the boulder nissan, I'd say it may be possible to see them churn out 800 wheel @ 22-23psi. The only thing that sucks is that'll probably be on race gas, I've seen Dan's supra dyno at 670 wheel @ 21psi on pump gas. Be awsome if they could achieve such high numbers on pump gas

Of course tho... I'm being optomistic

 

its all about how big of a turbo your using as to how high you can go on pump gas. a big single on a z should be able to get similar numbers on 93 oct. its all about keeping the boost as low as possible with the most cfm at that pressure, to keep internal compression from increasing cylinder pressures too much causing detonation.

 

If I recall correctly is Bolder Nissan useing the Crawford Plenum on a few high boosted >14psi setups?

 

Yea I have visited their shop and seen the Car as well as a customers car with its engine on an engine stand with the turbos bolted on the sides pretty cool sight!

They said the evidence of lean conditions was so great in the #5 and # 6 cylinders that they would strongly advise those going F/I to not use the factory plenum.

They just called me about 30 min ago my V5 Crawford Plenum finally arrived today .

Their car BTW once the fuel system is upgraded will be running 20 psi+ boost with the crawford plenum.