All:

I had my Eagle Talon TSi for about 4 months now and have only simple mods on it (see signature). I've been fiddling around with the car and getting a feel for how it behaves after adding mods to the car. The other night, I was very disappointed in the car.

Ever since 1989, I've always owned a turbocharged car. I was shocked to notice that the 4G63 motor doesn't have enough HP to push it to the redline in the higher gears (4th and beyond). This is a major weakness with the car. With a motor that has probably the most power potential for a 4-cylinder, I expected more. I only have 3" turbo-back exhaust, high-flo cat, and K&N cone with a hacked MAF, but I've noticed that the car struggles to get to 7000rpms from 6000rpms in 4th gear.

I'm going to try and tap all the power from this 14b, but I'm a little surprised that my ProbeGT turbo with exhaust, and intercooler pipes could probably walk down my Talon on the topside. It has a smaller turbo, and stock downpipe and cat and it feels much stronger on the top end.

A lot of people have been telling me that when I upgrade the turbo, the car will wake up on topside. That can't be the *ONLY* solution to this problem. I've even noticed on dynos with L2R turbos, that it looses steam after 6500rpms. In contrast, my T04E turbocharged RX7 TurboII was still making power well after the dyno run ended (upper 6500rpms)..

What's the deal with the 4G63 motor on topside? How can more power be tapped from this motor without changing the turbo? It has been said that the 14B can give up to 250WHP! How can I obtain this HP?

Super AFC-II has been ordered. Since this car creeps to 17psi on this exhaust, I'm running lean. We'll see if we can't make this car run 18psi on the stock fuel system by turning up the injector pulse width and richening up the fuel a bit. EGTs went way too high last night (1650F in 4th after 6000rpms).

More to come on this bird called "Phenyx"....

-M

I think it has to do with the design of the intake manifold. I've seen dynos of aftermarket intake manifolds that just kept pulling. I'm sure someone else will chime in with more info.

Yes, I'm hoping this is a long discussion.

I don't think its the intake manifold though. The 1G has a pretty big manifold. Considering, the ProbeGT does have a 2.2 liter, but the turbo is only an IHI which is about as small as a T25!!

-M

huh, thats odd my friends stock 90 TSI runs up to 8,000 in 4th....and 7,000 fairly easy in 5th although it struggels to get above 7k... I think it's fairly impressive since it's stock only mod to it other than he hallowed out the CAT is he choped the airbox.. otherwise 100% stock.

you sure your engine is runing top notch?

May also want to take in consideration of heat soaking your IC. Not that 17 psi is not to far out side the effiency range, it's still not optimum. I've noticed the same from my many experiances with my car and others. After preping most of the supporting mods in anticipation for the larger turbo I managed to free up my little T-2-5mall a bit. Porting will help also. After the turbo swap though it's night and day. I can pull all the way to 7000-7500 in 2nd and it's almost like a 3rd wind. After the turbo rewinds itself in 3rd u can feel it engage again. It's not ready to give up yet. Another factor that plays more into this than the 4G63 is the turbine side of the turbo. The TDO5 with the 14B turbine isn't very effient at higher RPMs. Just like comp wheels have effiency maps, turbines have theirs too. Don't know about the Probe, but the TO4E on the REX seems to be well balanced for the amount of boost desired and the ability to generate that boost by flowing the exhaust out. Remember the turbo is a giant air pump and can only move as much in as it can out. But u already knew that Hope this helps!

With a 16G i am sure that there will be some loss in the top end but not like it is now with the 14B. Like you said you egt's were soaring up pretty high i am sure that has alot to do with the lack of power in the top end. If you get those temps in check and cool your top end will pull alot harder.

Originally posted by RipperXX
huh, thats odd my friends stock 90 TSI runs up to 8,000 in 4th....and 7,000 fairly easy in 5th although it struggels to get above 7k... I think it's fairly impressive since it's stock only mod to it other than he hallowed out the CAT is he choped the airbox.. otherwise 100% stock.

you sure your engine is runing top notch?

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8k? you mean 7500?

If your running lean on the stock fuel system, then simply adding an S-AFC isn't going to help. How can you add more fuel when there isn't any more fuel to add. I would get a Fuel pump first, that should help the injectors flow abit more. Also the SAFC can't change IPW.

Originally posted by RipperXX
huh, thats odd my friends stock 90 TSI runs up to 8,000 in 4th....and 7,000 fairly easy in 5th although it struggels to get above 7k... I think it's fairly impressive since it's stock only mod to it other than he hallowed out the CAT is he choped the airbox.. otherwise 100% stock.

you sure your engine is runing top notch?

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This car is a very clean and top notch stocker. Last time on the dyno, it was reading perfect a/f ratios. But it didn't have exhaust and boost was only at 13psi.

The car, even then, didn't show enough "ummph" at the top end. Please note, that I'm not saying I can't *DO* top end.. It's just that it looses the pull after 105mph in 4th gear..

Originally posted by CanadianTSi
If your running lean on the stock fuel system, then simply adding an S-AFC isn't going to help. How can you add more fuel when there isn't any more fuel to add. I would get a Fuel pump first, that should help the injectors flow abit more. Also the SAFC can't change IPW.

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There isn't a pressure loss at the fuel rail. I'm running lean because of the hacked MAF which leans out the mixture even more so that you don't reach fuel cut. The SAFC will allow the car to inject more fuel into the cylinders and compensate for that loss. The fuel pump isn't quite taxed yet. The pump will be forthcoming however..

-M

Originally posted by ASZRAEL1266
With a 16G i am sure that there will be some loss in the top end but not like it is now with the 14B. Like you said you egt's were soaring up pretty high i am sure that has alot to do with the lack of power in the top end. If you get those temps in check and cool your top end will pull alot harder.

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Raul,

While the 16G has a bigger compressor wheel, the turbine side is still the stock 7mm housing and wheel. Therefore, you will get the same restrictions as I on top end. You should get more power, but your wheel will also be inefficient.

-M

another thing that will help the engien run better up high is a good set of cams. even the hks 264's will make a giant difference.

I find this to be kind of strange. I don't have a direct apples-to-apples comparison, but on my 2G, the 14b "Wakes up" at 5 Grand, and doesn't quit until the rev limiter spoils the party. Granted, I am running a '95 manifold, which is gasket-match ported, ported 14b, ported O2, test-pipe, intake, and of course the infamous 2G 8.5 pistons, but the characteristics of the turbo shouldn't change THAT much. I think that your turbo is really just struggling against the limitations of your manifold and stock setup. You have already taken care of the flow restrictions downstream of the turbo, and you have a 1G, which means that your head and throttle body flow more air. Have you thought about switching to a ported '95 style manifold, and porting your 14b and O2 sensor? What about some intercooler piping to replace the restrictive stock units? Putting in a larger fuel pump along side the SAFC would allow you to run up to 21 LBS on the little 14b. These things in conjunction would definately wake up the top end of your machine, without having to go with the 16G setup.

Matt.

Originally posted by Enraged78
I find this to be kind of strange. I don't have a direct apples-to-apples comparison, but on my 2G, the 14b "Wakes up" at 5 Grand, and doesn't quit until the rev limiter spoils the party. Granted, I am running a '95 manifold, which is gasket-match ported, ported 14b, ported O2, test-pipe, intake, and of course the infamous 2G 8.5 pistons, but the characteristics of the turbo shouldn't change THAT much. I think that your turbo is really just struggling against the limitations of your manifold and stock setup. You have already taken care of the flow restrictions downstream of the turbo, and you have a 1G, which means that your head and throttle body flow more air. Have you thought about switching to a ported '95 style manifold, and porting your 14b and O2 sensor? What about some intercooler piping to replace the restrictive stock units? Putting in a larger fuel pump along side the SAFC would allow you to run up to 21 LBS on the little 14b. These things in conjunction would definately wake up the top end of your machine, without having to go with the 16G setup.

Matt.

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Well said. There are a couple of points I'd like to make though. We aren't talking about my car specifically but all 4G63's in general. Most of them have been known (especially the AWD) to not have a good top end. Many of my friends with DSMs were walked continuously on topside (in the old days).

I would never consider a 16G simply because, in my opinion, its not a powerful enough turbo upgrade. I will immediately go with the L2R or anything that requires a much bigger compressor housing. This is because, you are guaranteed to gain at least a 50% increase in power. But there is much power to be tapped in this 14B and I'm wondering how to get it. I will get a fuel pump and upgraded intercooler pipes (well, at least the upper) in the near future.

-M

Just out of curiosity Phoenyx, what was the redline on your Probe and Rex?

My 7 was a non turbo and i know the non turbos could rev alot higher then the turbos. I would run up past the 8k mark on my tack and i could hear it reving higher and still pulling. The non turbos hold up to abuse very well they swing pretty good too.

If you bolt up 16g, turn up boost and do some tuning you will get 50% increase in hp. I don't see a reason to buy something big just for that. There has to be something wrong with your car if it struggles from 6k RPM. I did 4th gear pulls with T25 and never experienced what you did. Sure you feel it losing steam but it never struggled to hit rev limit in 4th.

Instead of hackin up your MAS, you should buy 2G one or LS1 MAF translator that just came out and is being discussed in tuning forum. If you'd like you can PM me, I might have 2G MAS available with a connector for cheap.

Originally posted by asian312
Just out of curiosity Phoenyx, what was the redline on your Probe and Rex?

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Probe: 6000rpm
RX7: heheheh, I had the Haltech computer so I set the redline at 7500rpm.

-M

Excuse me for stating the blaring obvious here, but just how hard do you expect a 13 year old, 3300 pound, heavy AWD drivetrain, 250HP car to pull over 105mph?? If you wanted top end, you should have bought a FWD. I don't think anything is wrong with the car. It's like buying a Honda Civic, and then wondering why you are getting beat by Porsches since you've seen a Civic beat one in the Fast and the Furious and figured yours would do the same thing. If it was a problem with the car, it wouldn't just happen over 105mph, it would happen throughout the powerband in any of the higher load gears. I would say the remedy for your problem would be....hmmm..umm..what's that stuff we used to make back in the day?? Oh, HORSEPOWER!!

Regards,

Originally posted by NosLaser
Excuse me for stating the blaring obvious here, but just how hard do you expect a 13 year old, 3300 pound, heavy AWD drivetrain, 250HP car to pull over 105mph?? If you wanted top end, you should have bought a FWD. I don't think anything is wrong with the car. It's like buying a Honda Civic, and then wondering why you are getting beat by Porsches since you've seen a Civic beat one in the Fast and the Furious and figured yours would do the same thing. If it was a problem with the car, it wouldn't just happen over 105mph, it would happen throughout the powerband in any of the higher load gears. I would say the remedy for your problem would be....hmmm..umm..what's that stuff we used to make back in the day?? Oh, HORSEPOWER!!

Regards,

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Nice one smart mouth!

My Eagle Talon TSi has 83,000 original miles. Compare that to my 89 Probe GT with 175,000 miles and my 88' RX7 Turbo II 10th Anniversary at 110,000 miles (changed the motor once).

Your excuse for old age is abit ridiculous. Are you saying that a FWD car has a better engine, or drivetrain? Are you making the argument that a similarly equipped FWD Talon would pull the AWD with the same mods?

Oh, I never said anything was wrong with *my* car. I asked what was the weakness in the 4G63 on topside?

-M

i could agree with a few of these points. i think cams would help a lot in the top. i have a 90 1g n/t and i can rev it to 7k whenever i feel the need and it pulls pretty hard. i only have a full exhaust, injen intake, and taylor 8m wires, but it still goes pretty good. ive got the car to 100 mph and it was still going strong.

i think if you ported the 14b, put it to a port matched 95 mani, added some ic piping, and put in cams it would make a huge difference.

I think what he is saying is that FWD's have better top end pull than AWD's. I belive this is due to less horsepower being lost to the wheels, weight, and I think the gearing is a bit different in the AWD as compared to a FWD.

A GST with the same mods as a GSX would walk away from the GSX in the top end simply due to less power train loss. Even if they both run out of steam in the top end the GST will retain more power then the GSX. Other then that it would all be up to the driver.

...Nice one smart mouth!...

That's what I'm here for.

...Your excuse for old age is abit ridiculous. Are you saying that a FWD car has a better engine, or drivetrain? Are you making the argument that a similarly equipped FWD Talon would pull the AWD with the same mods?...

Is it? I think you are expecting a bit too much out of the car. Have you taken the car down the track yet? Your mph would be a good indication of how well running your motor is. For example, EVERY SINGLE air filter, exhaust, 17psi and fuel pump 1G DSM I have owned/put together has run 105mph or better in the 1/4 mile. If you are running 14.7 at 94 for example, then there is an issue there. See what I mean?

And YES, a similarly equipped FWD would walk down your car on the highway; less weight and less drivetrain loss due to the FWD transaxle, and lack of rotating parts (driveshaft, T-Case, rear end, extra pair of axles, etc.) I have owned a Turbo II RX-7, and my sister's bf has a Ford Probe GT turbo, so I'm familiar with both. AWD's aren't going to pull as hard on top end without making a bit more power to compensate for it.

Regards,

so would this make a fwd car better in this perspective, and is the hp loss from the drivetrain that much of a difference that it would take that much power away from the car due to the drivetrain. it seems weird that the car would struggle like that at top end. just the drivetrain wouldnt make that happen, especially since there is numerous cars on this site that run strong at that rpm.