Major weakness in the 4G63 motor...

[Phoenyx]

Originally posted by 2gTurboS
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.

Ok. I pose this argument then:

I am so confident that there is an issue with the 4G63 motor on topside, that I'm willing to say that a FWD DSM with stock boost, cat-back exhaust, and UIP would still lose to a ProbeGT Turbo with the same mods and they both being FWD!!!

Anyone care to test this argument?

-M

 

[ASZRAEL1266]

I still say it isn't pulling in the top becouseof your EGT's I am not sure if you put it in the post but your EGT gauge was pegged as far as it can go. I know that pulled the he!! out of your timing. I still think if you get your EGT's under controll in the higher boost then the car will pull strongly in the top end. You said the EGT's are up becouse you are running lean. We will see when you get your S-AFC. Oh and becarefull man i know running the car with your EGT's that high is not good. Your lukcy its not the 7 or that motor would be toast.

 

[Phoenyx]

Originally posted by NosLaser


That's what I'm here for.

I see.

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?

No, I have not taken the car to the track yet. When I get this lean condition fixed, then I'll update this thread with my findings. Right now, I need more fuel as it's obvious that the engine is starving for it with that high boost.

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.)

Ok. Agreed.

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.

Agreed again. But are you saying that there is nothing wrong with the 4G63 and its *ONLY* the weight factor and lack of horsepower loss to the drivetrain that causes it to scream to 7000rpm?

-M

 

[NosLaser]

...Ok. I pose this argument then:

I am so confident that there is an issue with the 4G63 motor on topside, that I'm willing to say that a FWD DSM with stock boost, cat-back exhaust, and UIP would still lose to a ProbeGT Turbo with the same mods and they both being FWD!!!

Anyone care to test this argument?...

That argument is completely ridiculous. First, they are two completely different cars. Second, I would venture to say that the DSM has a better cylinder head design although I can't say that for sure since I've never seen a Probe head, but it definately has more turbo and will likely make more power than the Probe. What is your point here? If my aunt had balls she'd be my uncle. In pool, if the ball had rolled 6 feet either way it would have went in the pocket. Now you are just talking nonsense when I really thought this thread was going somewhere. And nobody cares to test that argument because everyone's car has more mods than that. Your car doesn't pull on top end because it is heavy, it is AWD, something's wrong with it, and it's STOCK. My small 16G equipped Laser had no problem pulling to 181mph on radar in 5th gear on a 225/50/16 tire, and trapping 129mph at the track. I'd say that's plenty top end. I think your car has issues dude.

Regards,

 

[na90dsm]

Originally posted by Phoenyx


Ok. I pose this argument then:

I am so confident that there is an issue with the 4G63 motor on topside, that I'm willing to say that a FWD DSM with stock boost, cat-back exhaust, and UIP would still lose to a ProbeGT Turbo with the same mods and they both being FWD!!!

Anyone care to test this argument?

-M

i really dont think that a probe will walk all over a 4g63. my friend has a mx6 which is pretty much the same car with a few differences, but hes is a v6. his car i know for a fact is lighter than the dsm's, and i think his gears are shorter than ours too. but you are right on 1 point. i noticed when i get behind his car on the freeway, when i floor it to catch up to him, he does start to pull away at the top end a bit. he can rev out to 7500rpm and pulls really hard. granted hes a v6 but he still just walks away.

the 4 cylinder probe, i have raced a few and they didnt pull away from me that hard in the top end. granted at the time i was runnung with a clutch that was going, but he still didnt pull away that hard. i think at the time if i had my car running right i still coulda kept up with him. even though im n/t i still think i coulda gave him a run for his money.

you are right on the fact that they pull hard at the top end, but i think a 4g63 that was running correctly all the way through 7k would keep up if not pass him in the top end. there are a couple of probes and mx6's around where i live and enough dsm's to see these too race, ive seen a few and the dsm's came out strong and stayed that way until they both backed off. there is a pretty good match up between the 2 cars but the maiun reason for the probes being so fast is they have less weight.

 

[ASZRAEL1266]

hey nos laser did i read that right 181? My god that is a high speed. From what i have read about the 1G's is they run out of room around 160-170ish. Do get that 181 I think you would have to go past the rev limiter. My car doesn't have a problem hiting red line in 4th. I can't do it now becouse my clutch slips, but before that the tach wouldn't slow down at all when it was past 6k rpm.

 

[NosLaser]

Even the top speed calculator (can be found by searching the Talon Digest Archives) with the stock gearing, at 7400rpm, 225/50/16 is just over 181mph. This was on Police radar (cop gear-head friend) on US27.

Regards,

 

[Phoenyx]

Originally posted by NosLaser

That argument is completely ridiculous. First, they are two completely different cars. Second, I would venture to say that the DSM has a better cylinder head design although I can't say that for sure since I've never seen a Probe head, but it definately has more turbo and will likely make more power than the Probe. What is your point here?

My point is that:

First, you gave me the fact that the car doesn't pull on topend because of it's AWD character. That being that it has drivetrain loss and that the car weighs alot more than a similarly equipped FWD. My point is that I *still* think it's the engine because a similarly FWD car that's turbo can walk it on topend. You are saying that is a ridiculous argument, but if that were true, then the ProbeGT and DSM wouldn't have been compared so heavily back when they were released in the late 80's early 90s. I have proof of tests that were made by Motor Trend and Car & Driver on the two cars and how they behaved both in the quarter mile and on topend. My point still stands: What is wrong with the 4G63 on topend? I'm sure that adding enough power to the engine will make this a moot point, but that's simply my point. Can it be made very strong with a *STOCK* turbo?

If my aunt had balls she'd be my uncle. In pool, if the ball had rolled 6 feet either way it would have went in the pocket. Now you are just talking nonsense when I really thought this thread was going somewhere.

You are certainly welcome to ignore this thread! I'm not forcing you to comment. There are many people here that can give mature responses without coming off like they "know-it-all".

Your car doesn't pull on top end because it is heavy, it is AWD, something's wrong with it, and it's STOCK.....I think your car has issues dude.

You are correct! It does have issues! It's running lean!! As I'll say for the 4th time - Once I get my lean condition settled, I'll test it out again. Even before it was running lean, it still didn't seem quite strong on the topend, but of course, it only had boost/K&N cone.


Cheers,

-M

 

[na90dsm]

i know for a fact that the head design on the dsm along with the intake manifold and the throttle body is better than that on the probe and mx6. going from my friends mx6 his head design is good but doesnt flow as much as the dsm head. he blew one of the valves in his head and i had a chance to look at the heads on his car along with the intake manifold and the intake mani was very poorly designed. he goes on forums for the mx6's and probes and was considering the swap to a 4 cylinder turbo motor in favor of the turbo over his v6 n/a. i got into reading about the head design and the intake mani design and i found out that the intake mani thats stock on these car is a small diameter for the amount of air flow that is being passed through it. the head design is the same way.

one of the common swaps in my friends car is the intake mani from the stock mx6 mani to a KLZE intake manifold off of a j-spec motor. it has been stated that the j-spec itake manifold is about 20mm bigger in the intake runner over the stock manifold.and as for the head the ports and such are also bigger in the head itself.

 

[Antilles]

In my quest for a DSM I drove many, many stock AWD's. Several of which were "top notch, low mile, perfectly running" cars. Not a single one felt the same as the previous one. The slowest was a perfect 70k mile AWD. The fastest, and the one I bought, was one with a smokey turbo and bad rings. All of these cars were stock. After 10 years no one DSM performs exactly like another. I believe your car has issues.

Oh, and my stock, smokey, AWD DSM had no problem obtaining 125mph. Even pulled hard in 5th at 90mph.

Even if the car did "suffer" from "poor top end" it would not be because of the motor, it probably has more to do with the intake, from the MAS to the turbo to the throttle body.

And one more thing, at 17psi on stock fuel my car knocks like crazy. Hell, at 17psi with an upgraded fuel pump and supra IC it knocks like crazy. And I know from having a logger and lifter tick, that when the ECU see max knock, the car is DOG SLOW in any gear. So when you are way up near redline at 17psi in 4th and your IC is heatsoaked, you are probably getting very very poor timing. the difference in power between 20* of timing and 10* of timing is incredible.

chris

 

[Phoenyx]

Originally posted by na90dsm


i really dont think that a probe will walk all over a 4g63. my friend has a mx6 which is pretty much the same car with a few differences, but hes is a v6. his car i know for a fact is lighter than the dsm's, and i think his gears are shorter than ours too. but you are right on 1 point. i noticed when i get behind his car on the freeway, when i floor it to catch up to him, he does start to pull away at the top end a bit. he can rev out to 7500rpm and pulls really hard. granted hes a v6 but he still just walks away.

the 4 cylinder probe, i have raced a few and they didnt pull away from me that hard in the top end. granted at the time i was runnung with a clutch that was going, but he still didnt pull away that hard. i think at the time if i had my car running right i still coulda kept up with him. even though im n/t i still think i coulda gave him a run for his money.

you are right on the fact that they pull hard at the top end, but i think a 4g63 that was running correctly all the way through 7k would keep up if not pass him in the top end. there are a couple of probes and mx6's around where i live and enough dsm's to see these too race, ive seen a few and the dsm's came out strong and stayed that way until they both backed off. there is a pretty good match up between the 2 cars but the maiun reason for the probes being so fast is they have less weight.

Thanks for the comments. I agree that weight definitely has a factor in this. It just seems that the 4G63 is superior in every way to the FE2 motor (mx6/probe). I just expected a little more out of the 4G63 without going heavy into mods. I guess I was over zealous...

-M

 

[ASZRAEL1266]

That is somthing i can get into I use to have a 2G probe GT. The KLZE is biger and better then the KL03 but you won't see the diffrent untill more work is done. As it is now i know for sure a Stock probe GT will walk all over my car in the top end. My car pulled really hard up to 140 that is when it took a long time to gain more speed. Then again the gearing on the probes are A LOT shorter then the DSM's A 93+ GT with KLZE or KL03 will max out around 165ish due to gearing. I got mine to 150 the speedo was burried and the tach was moving extreamly slow. Once you get your lean issue worked out i am sure you will see a big diffrence in how it pulls. Look at your Dyno sheet from a month ago did the power drop off there also? I can't remember if it did or not. If it pulls hard in 3rd then it should pull hard in 4th unless somthing is stoping I.E. running learn due to some bad boost creep.

 

[Phoenyx]

Originally posted by Antilles
....After 10 years no one DSM performs exactly like another. I believe your car has issues.

Oh, and my stock, smokey, AWD DSM had no problem obtaining 125mph. Even pulled hard in 5th at 90mph.

And one more thing, at 17psi on stock fuel my car knocks like crazy. Hell, at 17psi with an upgraded fuel pump and supra IC it knocks like crazy. And I know from having a logger and lifter tick, that when the ECU see max knock, the car is DOG SLOW in any gear. So when you are way up near redline at 17psi in 4th and your IC is heatsoaked, you are probably getting very very poor timing. the difference in power between 20* of timing and 10* of timing is incredible.

chris

Now we are talking! I can believe that my car is knocking with the 17psi. I will remedy that shortly and then retest to see if the car is much better after 105mph. Like I said before, the car has no problems getting up to 105mph in 4th. It feels very nice! However, once the EGTs start to climb due to the boost being pegged at 17psi, my car feels dog slow.. Timing is probably being pulled hard as you said..

Stay tuned for round two!!

-M

 

[DeezNutsForYou]

maybe you should pull your turbo out and look at the turbine and compressor wheels, you could have some chips or missing blades. This could cause your lack in power. Just a though.

 

[na90dsm]

yes i agree. id check the car for any issues of boost creep and id also take a look at the fuel setup on the car. id check the injectors and make sure there clean and working good, and check the lines for any restriction in the fuel setup. for the boost creep id check the tb shaft seals, the turbo mani for cracks, the turbo for cracks, and just general stuff. its allways something simple that can cause a big problem.

 

[Phoenyx]

Originally posted by ASZRAEL1266
That is somthing i can get into I use to have a 2G probe GT. The KLZE is biger and better then the KL03 but you won't see the diffrent untill more work is done. As it is now i know for sure a Stock probe GT will walk all over my car in the top end. My car pulled really hard up to 140 that is when it took a long time to gain more speed. Then again the gearing on the probes are A LOT shorter then the DSM's A 93+ GT with KLZE or KL03 will max out around 165ish due to gearing. I got mine to 150 the speedo was burried and the tach was moving extreamly slow. Once you get your lean issue worked out i am sure you will see a big diffrence in how it pulls. Look at your Dyno sheet from a month ago did the power drop off there also? I can't remember if it did or not. If it pulls hard in 3rd then it should pull hard in 4th unless somthing is stoping I.E. running learn due to some bad boost creep.

I'll post my dyno sheet soon. It does pull very hard in 1st, 2nd, and 3rd, but while in 3rd, in the upper rpms, it is starts to creep. Once I hit fourth, the boost is pegged at 17psi and the EGTs start to soar..

-M

 

[Phoenyx]

Originally posted by na90dsm
yes i agree. id check the car for any issues of boost creep and id also take a look at the fuel setup on the car. id check the injectors and make sure there clean and working good, and check the lines for any restriction in the fuel setup. for the boost creep id check the tb shaft seals, the turbo mani for cracks, the turbo for cracks, and just general stuff. its allways something simple that can cause a big problem.

The car is in perfect condition. The engine bay is emmaculate and most hoses, clamps, lines, knobs, etc.. are in great shape. I doubt seriously if there is anything wrong with the car. I'm not indicating that my car has a problem other than the lean condition due to the recently installed 3" turbo back exhaust. Before this, I had no creep of any kind.

-M

 

[na90dsm]

just outta curiosity what octane gas are you running. and the manifolds on the dsm's along with the turbo housings and such are known to crack. id check it anyway especially since your egt's got that high.

 

[Norcal2004]

wats a L2R turbo?

 

[Norcal2004]

wats a L2R turbo?

 

[Antilles]

[ralph]whats a battle?[/ralph]

I'm gonna go ahead and take a quick guess that your...um...new. The L2R is a 50 trim hybrid sold by AGP turbo. But that has nothing to do with this thread, so you would probably get much better results asking elsewhere, searching, or making your own thread.

 

[Polska Power]

This is my first post on this web site although I have been a member of DSM Talk and Canadian DSM for a number of years and have owned DSMs since 1993. I find it curious that you would quote "Motortrend" and "Car and Driver" to bolster your argument. Are you sure you know what your talking about?? Car and Driver, July 1989. Ford Probe GT 0-100 in 19.8 seconds (fast) 15.3, 90 miles an hour in the quarter mile, top speed 134 miles an hour. Mitsubishi Eclipse GS Turbo 1-100 in 18.5, 15.1 quarter mile, 93 miles an hour, top speed 143 almost 10 miles an hour than the Probe GT. Interestingly enough they have a test of an AWD Talon that was also quicker in the 0-100 than the Probe GT, 18.1.
Motortrend, Aug 1990. Probe GT 0-80 12.9, quarter mile 15.8, 89 miles an hour. Laser RS 0-80 12.0, quarter mile 15.5, 92.7 miles an hour. In fact, in the Motortrend article they even mentioned that the Laser had more top end than the Probe GT and the Probe sounded laboured and coarse at higher rpms. Don't believe it, look it up. Next time you quote magazine articles you should get the information correct. Also, I had a friend with a Probe GT and whenever we raced on the highway with my previous FWD, I always smoked him. I think your car must have some problems. Thank you.

Polska Power
95 TSI AWD Dark Green
16 G, exhaust, the usual mods.

 

[DrZiplok]

Originally posted by Phoenyx

You are correct! It does have issues! It's running lean!! As I'll say for the 4th time - Once I get my lean condition settled, I'll test it out again. Even before it was running lean, it still didn't seem quite strong on the topend, but of course, it only had boost/K&N cone.

This entire discussion is pointless; your car is out of tune, the ECU is trying it's best to save you from some serious repair bills and you have the gall to complain that it's "not strong"?

Someone probably has a "you don't deserve this car" graphic; if they don't chime in, pretend I do.

 

[4TireFire]

Just wanted to throw in my 2 cents here, My 91 talon with increased boost and full 3" exhaust struggles over 6k. BUT if i turn the boost back down to stock levels the problem goes away and the car pulls clean to 7 grand! This may indicate the computer pulling back the timing due to detonation or a lean condition. The more i drive my car and read posts i am convinced Hardwiring a aftermarket fuel pump fixes half the problems people seem to have with their DSMs. I know when i installed mine boost cut dissappeared, timing problems were reduced, and the engine now pulls strong to 7K in any gear.
OK, maybe that was 3 cents but i wanted to suggest a cure here.

 

[Phoenyx]

Originally posted by Polska Power
This is my first post on this web site although I have been a member of DSM Talk and Canadian DSM for a number of years and have owned DSMs since 1993. I find it curious that you would quote "Motortrend" and "Car and Driver" to bolster your argument. Are you sure you know what your talking about?? Car and Driver, July 1989. Ford Probe GT 0-100 in 19.8 seconds (fast) 15.3, 90 miles an hour in the quarter mile, top speed 134 miles an hour. Mitsubishi Eclipse GS Turbo 1-100 in 18.5, 15.1 quarter mile, 93 miles an hour, top speed 143 almost 10 miles an hour than the Probe GT. Interestingly enough they have a test of an AWD Talon that was also quicker in the 0-100 than the Probe GT, 18.1.
Motortrend, Aug 1990. Probe GT 0-80 12.9, quarter mile 15.8, 89 miles an hour. Laser RS 0-80 12.0, quarter mile 15.5, 92.7 miles an hour. In fact, in the Motortrend article they even mentioned that the Laser had more top end than the Probe GT and the Probe sounded laboured and coarse at higher rpms. Don't believe it, look it up. Next time you quote magazine articles you should get the information correct. Also, I had a friend with a Probe GT and whenever we raced on the highway with my previous FWD, I always smoked him. I think your car must have some problems. Thank you.

Polska Power
95 TSI AWD Dark Green
16 G, exhaust, the usual mods.

I never mentioned quarter mile times. I specifically was referring to an article in Motor Trend where they tested the laserRS turbo and the ProbeGT in a 4th gear roll along test. The ProbeGT was ahead from 40-120mph. In any case, I wasn't talking about topend speed, but the acceleration to get there!

Again, my car is probably pulling timing due to the overboost condition.


-M