I'm considering the APS Extreme TT. Anyone running the APS Extreme on a built 3.5L engine? If so, any problems with lag?

One would think because of the bigger turbos found in this kit there would likely be around 200-300 rpm delay/lag (vs. the standard APS turbos). That's why I was considering stroking the engine? But if it's not necessary I would prefer not to, and just keept it a 3.5L setup.

Thanks.

 

man this is a lonely thread! no you dont have to stroke but cubes are always nice.

 

200-300rpm lag? Do you ever leave 6th gear or is this really an issue?

 

Check out this thread:

https://my350z.com/forum/forced-induction/266211-my-gtm-420ztt-retuned-dyno-charts-included.html

APS Extreme kit and fuel system using the F-Con for tuning. 4.24L GTM stroker kit. He augmented with water/meth though... GTM has a shop car in the upper 800's running some custom gear, but still using the APS Extreme. There was some debate in a thread or two about the "optimal" setup for a boosted VQ and the theory was that an over bore vs. a stroker setup was more efficient. Sharif has a GReddy TT setup with a built 100mm over bore (stock stroke) putting down mid-600's IIRC.

Bottom line is increasing the displacement on these cars only helps. Whether you go 3.8 stroker or 3.8 over bore is still a bit of a question mark. Going for both has been proven to be extremely effective in generating nasty power levels...

I heard a rumor that George@GTM is going for a 3.8L stroker on his current build up. Maybe he can chime in as to the expected results. I'd be curious to see the difference in numbers and power curve between Sharif's and his setup...

 

I'd prefer to keep it stock or .20 overbore. There are better headgaskets on the market that are more suitable to combat headlift. I'm interested in what headgasket solution people are using in larger bore builds.

 

I think Sharif is running the cometic 100mm hg's IIRC. I agree that stock (or close to it) bore size helps with the ability to appy the HKS hg's (which are 97mm ONLY). For that reason too, I went with 96mm pistons in my engine with the HKS hg's. But Sharif's car is holding up well I'm told. Also, I would think that all of the 4+L strokers out there are running the cometics as well.

I think a lot has changed lately with headstud selections as well as tuning knowledge. Across the board, we're seeing less issues with headlift as a result and the cometics are holding up better. I completely agree that the HKS hg's is the way to go, but for the big over bore / stroker setups, there doesn't seem to be any other solution...

Now if HKS would only put out a 100mm hg set............

 

We have been using stock-size L19 head studs with Cosworth/Cometic 100mm hg's and haven't had a single problem yet ranging from 500-1000+hp

 

I agree, a stroker setup may not be necessary - but if it is within budget I would definitely go for it - in addition to the decreased lag, you will also make more power.

 

That's the engine package I was considering, actually.

A built 3.8L with an APS Extreme TT is the ideal combination. Still wondering if there's anyone out there using the 3.5L with Extreme TT and what issues, if any, they are experiencing...

Thanks everyone for your input thus far.

 

DDS,

Here is my $0.02.

The APS Extreme turbos can certainly take the displacement increase without too major a detriment to the torque curve quality.

It all depends on what you precisely want out of the car...Do you seriouosly road race, in which case you'd want to be much more careful if you are striving for a flat torque curve. Or are you going all out without much consideration for the said fact, in which case just go for the largest displacement you can afford.

Personally, if it's the former, i'd go for a milder increase in displacement, so that the increase in the manifold backpressure (in the turbine housing) is not as great as it would be in higher displ. engines, so that it would still maintain a higher relative top end torque vs torque peak number. Ideally, you are looking for a drop in the torque number that mimics the drop in engine's naturallly aspirated inherent VE for your head/cam setup. I currently don't know those numbers and can only predict them. So, just do a low psi run on your car (the lowest you can), with a good tune, and note the relative redline torque number divided by peak torque number, as that would correlate to the best case scenario that you can strive to maintain with higher boost setups. My point here, is that the relative redline/peak torque relationship on a higher displacement engine (say, a 4.2) at the same Boost setting (and same redlines) would be lower than on a lower displacement engine (say a 3.8 stroker) due to the increased backpressure in the turbo manifolds and hence effectively lower VE, while the actual torque numbers would be higher in the higher displ. engine. So, if you care about a flatter/more refined torque curve, then you have to care about such things, otherwise your budget is the limiting factor.

 

pm Westpak on the forum. I believe he installed an extreme TT on a 3.5l block a few months ago on one of his customer's 350z.

 

APS Extreme TT: Does it deserve a stroke?


I'll stroke to the APS Extreme TT any day...

 

^^^ I knew that comment was coming sooner or later from somebody!

 

We did the Extreme APS TT on Dutchboy's car with our standard S1 shorblock (96mm bore), and there was a little bit more lag than the regular APS kit. Full boost in 5th gear hits at about 3800rpm, vs. about 3300rpm for the regular APS TT kit. I wouldnt call it laggy, just a little smoother and linear in power delivery, rather than a harder power build up.

L19's are 100mm are in my engine with no issues. I think IP's test to 1000whp+ supprts the idea, that the L19's are prefectly fine.

 

+1. That's the best way to describe the feel of the car. The power comes on so smooth, and it keeps pulling hard to about 7,000 rpms. It's very controllable for a 500+ whp car on street tires.

 

Proof that a certain amount of "lag" can sometimes be a good thing.

 

a stroker is ideal for this kit but its not a must. i contimplated this also but decided the regular aps tt kit is more then enough for my power goals. BUT if i could do it all over again i would get the extreme kit simply for the fuel setup and bigger turbos and ex wastegates. if you plan to run 500-600rwhp then the lag really wont be to much of an issue.

cliff notes: get the extreme kit

 

You guys have all been real helpful. Thanks again for your time.

I stopped by Jotech today for their input on this matter and spoke with Kenny Tran (spent a good hour and half with him...cool guy). Kenny highly recommended this set-up:

-Greddy TT on a built 3.5L engine (short of sleeving)
-1000 cc HKS injectors (return fuel system, rails, pump, regulator, lines, fittings)
-HKS F-con
- Greddy TT exhaust with test pipes


This is obviously the short list, and he said this system has been proven (plus, he's highly familiar with this setup). So I'm thinking I may just follow his advice on this. Plus, my goal is to have a fast street car (i'm not much into tracking my car).

Question: Would kenny's set up (that I listed above) be more optimal for street car applications versus an APS Extreme TT on a 3.5L engine?? (Which set-up would produce a quicker car?)

I'm particularly interested in what Gurgen and Sharif have to say about this. Sharif, I left a message on your machine Friday evening about parts. Please return my phone call. Thanks.

 

Well it really depends on your budget. The APS Extreme kit, while being more expensive already includes all your fuel system needs. Not to mention the Garret turbos that come with the kit are superior to the GReddy Mitsu turbos ( which will need to be rebuilt more often than a Garret unit.) The APS kits quality is OEM and a great kit! IMO a 4.0L stroked engine would compliment this kit perfectly! (but not a must)

-George
GT Motorsports

 

DDS,

OK..here is the deal (my $0.02)

What are your power goals? APS Extreme will make more power than Greddy, plus you get much better turbos, but if oyu are going to run lower levels of boost, Greddy will fit the bill wrt to efficiency well, plus save you some money. The APS is far more complete though, and the fuel system is a nice bonus (injectors). Now, that fuel system already comes with injectors, etc... etc...

Regardless,

Kenny Tran is wrong on at least one point: do not use the HKS1000cc injectors... they are not built for our valve/intake geometry; however some say that it's not that important and I would not completely disagreee with them. The best injectors to get would be the PE 650 or 800 (these are only at 2.5bar). They are specifically designed to have the spray angle taht complements the intake valve placement (i.e. their distance from the injector and b/w one another).

Not talking crap about Kenny Tran, but getting unbiased advise is sometimes difficult. To make HKS injectors fit requires some machining of the intake runners...just being objective. The PE injectors can be had for $200-300 less than HKS ones on the street.

I'd definitedly do the Greddy TT exhaust...agreed. It's a great-sounding exhaust with dual 2.72" piping. If you get Greddy, i'd definitely get the 3" turbo-back test pipes, and not the 2.25" ones (i hope I am correct on the exact diameter). Whether greddy with 3" test pipes, or APS (which already comes with 3" outlets on ther 3.5" pipes), you'll need to cut off and redo the inlets on the greddy TT exhaust, as they are tapered to a smaller 60mm diameter...so you'll have to get the shop to cut off the existign flanges, use a pipe expander to get it up to a 3" ID and weld on a new flange (or alternatively use 3" pipe sections with flanges and cut off the entire tapered down section of the exhaust and weld on teh new 3" piping/flange inlets).

HKS Fcon is a minimum must IMHO, but I am buttier than average when it comes to EMS's.

HTH