Help with soft pull after mods

[KrackaC8]

Having flashbacks to DSMTalk/DSMTuners/EvolutionM at the moment...

 

[thesilverbullet]

i would start with bleeding the new heat exchanger to remove any trapped air…

 

[toki]

Even if the radiator and engine coolant are in perfect working order, coolant issues in an air to water intercooler system on its own can cause engine overheating.

A malfunctioning charge air coolant system cannot cause engine overheating. It may contribute to engine overheating by failing to remove the extra heat caused by compression, but you have to be introducing that extra heat in the first place. You can drive under vacuum with a malfunctioning charge air cooling system and have no problem with engine temperature.

I was responding to the claim that "The heat exchanger would not impact anything but your coolant temps, and you would see that in the temp gauge." That was kevin's statement, and it is false for fairly obvious reasons. You will not necessarily see engine overheating solely because of a malfunctioning charge air cooling system. Assuming OP hasn't been completely careless and continued to do back-to-back WOT pulls on his car that he knows is having problems, it is unlikely that he has put himself in a position where, if he does have a problem with the charge air cooling system, it would have caused engine overheating.

 

[Xylander]

Well, what you guys are missing is that if the heat exchanger were bad, the car's performance would be abysmal, long before the thing let the turbos go molten red and overheat the engine. If your charge air gets too hot, the car will pull timing and you'd be down on power to the point where, hopefully, the driver would stop and turn the damn thing off. But yes, a failed heat exchanger CAN cause high engine temps, but only if the driver is stupid and continues to ignore the obvious.

 

[Drago86]

Exactly, persistent HIGH IAT's will lead to heat soak, which will cause the engine to overheat, and that will register on the temp gauge. You are absolutely correct.

No it absolutely will not, it will increase the tendancy for engine knock, and cause knock retard and possibly lowered boost but has absolutely nothing to do with the engine coolant temp.

The heat exchager is for lowering iat, it has nothing to do with the coolent temp except tangentialy through the knock retard.

 

[kevinbonds]

No it absolutely will not, it will increase the tendancy for engine knock, and cause knock retard and possibly lowered boost but has absolutely nothing to do with the engine coolant temp.

The heat exchager is for lowering iat, it has nothing to do with the coolent temp except tangentialy through the knock retard.

If your intercooler is not working or improperly bled, it will eventually cause the engine to run hot, which will manifest itself in the engine coolant temp gauge. It’s a fact, in a turbo car as compact as the VR30 the engine will run hot with a bad HX. It’s hard to believe this needs to be explained.

 

[Drago86]

If your intercooler is not working or improperly bled, it will eventually cause the engine to run hot, which will manifest itself in the engine coolant temp gauge. It’s a fact, in a turbo car as compact as the VR30 the engine will run hot with a bad HX. It’s hard to believe this needs to be explained.

No it's hard to believe you actually think that. The car will just run like crap and be way down on power or possibly blow up depending on how the ECU deals with it. There have been turbocharged cars with no intercoolers from the factory, they do not overheat. The 280zx was one of them.

Cooling the charge air has NOTHING to do with cooling the engine, it's to prevent knock.

 

[kevinbonds]

No it's hard to believe you actually think that. The car will just run like crap and be way down on power or possibly blow up depending on how the ECU deals with it. There have been turbocharged cars with no intercoolers from the factory, they do not overheat. The 280zx was one of them.

Cooling the charge air has NOTHING to do with cooling the engine, it's to prevent knock.

Ok, thanks for the info

 

[takemorepills]

You guys are getting into the weeds. The OP didn't mention high coolant temperature, he mentioned poor performance. Which does sound like improper operation of the air/water intercooler, meaning that's one of a few plausible things.

Someone asserted that poor IC performance would show up on the coolant gauge, as if it'd be immediate and definite. That's not entirely true, as stated. It's not wrong, either. That's not worth bickering about when OP didn't mention it

The Z chassis has long suffered from marginal cooling due to the design of the front end. One of my Z31s loved to overheat for the slightest of issues. This is very possible on the new Z too. Over time I can see how the slightest cooling inefficiency would end up as high coolant temperature. But, in winter? It'd probably take a bunch of driving of an obviously malfunctioning car to get that to occur.

I'd let OP have his tech sort out the issue they created, absolute statements like "the heat exchanger would not impact anything but your coolant temperature" was definitely wrong. It would immediately show up as reduced power long before overwhelming the engine cooling system in winter.

 

[MAPerformance_]

I have a 2024 z.
Had someone install an ams cold air intake, ams heat exhanger etc.
Car was running fine etc, then slowly felt like being dragged. Found out thay he dodnt put the undershroud back. Had a different shop reinstall the z1 aluminum shroud. Not sure if these guys did it right. Scrapping speed bumps, whistling during deceleration( intermittently) and doesn't pull hard anymore. Its been weeks I thought it might just be adjusting. Did an ecu reset and relearning. Something might have gotten dislodge during undershroud installation? Or something else

Yeah, something’s not right. The car shouldn’t “adjust for weeks,” especially after an ECU reset/relearn. A soft pull + new noises after undertray work is a big red flag.


A few thoughts, in order of likelihood:


1. Boost / intake leak (very likely)
Since this started after the undershroud mess + reinstall:

• AMS intakes + heat exchanger = a lot of piping and couplers
• It only takes one slightly loose clamp or misaligned coupler
• Whistling on decel screams boost leak or intake air leak
• Soft pull = you’re not hitting target boost, ECU is probably pulling timing or limiting power

I’d 100% smoke test the intake/boost system. Don’t guess. A good shop can find this fast.


2. Undershroud installed wrong / rubbing
Scraping speed bumps is not normal even with the Z1 aluminum shroud.
Possibilities:

• Shroud mounted too low
• Wrong hardware/spacers missing
• Shroud pushing against intercooler piping or charge pipes
• Flexing at speed and contacting something (causing whistle)

If the shroud is contacting piping, that could:

• Slightly unseat a coupler
• Cause intermittent leaks
• Make noise only under certain throttle/decel conditions

I’d have the car on a lift and physically check clearance everywhere.


3. MAF / intake alignment
AMS intakes are solid, but:

• If a MAF is slightly rotated or not seated right
• Or wiring is tugged / stressed
  The car will feel “lazy” without always throwing a CEL.

Check:

• MAF orientation
• MAF harness fully clicked in
• No intake pipe rubbing or being preloaded by the shroud

4. Heat exchanger install side effects
Less common, but worth checking:

• Any pinched hoses
• Coolant level (low can cause timing pull)
• Nothing blocking airflow weirdly under the car

5. ECU “learning” excuse
Nah. The VR30 adapts, but:

• It doesn’t take weeks
• It doesn’t adapt down permanently unless something’s wrong
  If it feels worse than before, it’s mechanical, not software.

What I’d do next (in this order):

1. Get it on a lift
2. Inspect undershroud install (height, spacers, clearance)
3. Smoke test intake/boost system
4. Re-torque all intake and charge pipe clamps
5. Check MAF seating and wiring
6. Verify coolant level

If you want to be extra sure, log:

• Boost target vs actual
• AFR
• Timing

But honestly, I bet money it’s a boost leak or shroud interference caused during reinstall.


You’re not crazy — the car should pull harder with those mods, not feel like it’s dragging an anchor.

 

[Tasigur09]

Yeah, something’s not right. The car shouldn’t “adjust for weeks,” especially after an ECU reset/relearn. A soft pull + new noises after undertray work is a big red flag.


A few thoughts, in order of likelihood:


1. Boost / intake leak (very likely)
Since this started after the undershroud mess + reinstall:

• AMS intakes + heat exchanger = a lot of piping and couplers
• It only takes one slightly loose clamp or misaligned coupler
• Whistling on decel screams boost leak or intake air leak
• Soft pull = you’re not hitting target boost, ECU is probably pulling timing or limiting power

I’d 100% smoke test the intake/boost system. Don’t guess. A good shop can find this fast.


2. Undershroud installed wrong / rubbing
Scraping speed bumps is not normal even with the Z1 aluminum shroud.
Possibilities:

• Shroud mounted too low
• Wrong hardware/spacers missing
• Shroud pushing against intercooler piping or charge pipes
• Flexing at speed and contacting something (causing whistle)

If the shroud is contacting piping, that could:

• Slightly unseat a coupler
• Cause intermittent leaks
• Make noise only under certain throttle/decel conditions

I’d have the car on a lift and physically check clearance everywhere.


3. MAF / intake alignment
AMS intakes are solid, but:

• If a MAF is slightly rotated or not seated right
• Or wiring is tugged / stressed
  The car will feel “lazy” without always throwing a CEL.

Check:

• MAF orientation
• MAF harness fully clicked in
• No intake pipe rubbing or being preloaded by the shroud

4. Heat exchanger install side effects
Less common, but worth checking:

• Any pinched hoses
• Coolant level (low can cause timing pull)
• Nothing blocking airflow weirdly under the car

5. ECU “learning” excuse
Nah. The VR30 adapts, but:

• It doesn’t take weeks
• It doesn’t adapt down permanently unless something’s wrong
  If it feels worse than before, it’s mechanical, not software.

What I’d do next (in this order):

1. Get it on a lift
2. Inspect undershroud install (height, spacers, clearance)
3. Smoke test intake/boost system
4. Re-torque all intake and charge pipe clamps
5. Check MAF seating and wiring
6. Verify coolant level

If you want to be extra sure, log:

• Boost target vs actual
• AFR
• Timing

But honestly, I bet money it’s a boost leak or shroud interference caused during reinstall.


You’re not crazy — the car should pull harder with those mods, not feel like it’s dragging an anchor.

Ty man! Ill show this to the shop! And hopefully do this

 

[thesilverbullet]

Oh my - this is not resolved yet? I hope they get you fixed up soon.

 

[Tasigur09]

I couldn't find a shop that wants ti do it. The shop i went to just bled it but didn't smoke test anything or re torque anything. I have another shop lined up but won't be able to take me till they have an opening

 

[Tasigur09]

Ty man! Ill show this to the shop! And hopefully do this

I showed to the shop, they smoke test it no leaks, they said they checked the undershroud and re torqued the clamps.
The torque is still not there , atleast in thr lower gears. Slightly better shove in higher gears.
I mean they could have easily not followed your directions aside from the smoke test. They recorded it thags why know they did that atleast

 

[BigBlue]

It's not irrelevant, you just don't know what you're talking about. Explain the mechanism by which high charge air coolant temperature necessarily causes engine overheating. Try not to copy and paste some word salad bullshit from ChapGPT.

Also, you should know that you sound like an idiot when you say "period" to shut down further conversation, as if you are the one who defines what is true or not. Considering you don't even change your own oil, and I actually wrench on this platform, including installing my own heat exchanger, I think the odds are pretty high that you don't have the high ground here.

Would it be fair to say if we're talking about charge temps that would be higher than normal due to air in the system the ECU would pull more timing than normal. Pulled/retarded timing = higher engine temp. Is it going to cause higher engine coolant temp? That hotter than normal heat exchanger does sit in front of the radiator so it ain't doing it any favors.