So what's the verdict on the Whipple 4.0L

[lthlvpr]

I know it was released a couple months ago. I've read the posts on the board which range from it works great, to having belt issues, to running out of fuel, to the stock airbox can pull enough air for it.

It seems to me it would be fairly easy to determine if it's working properly and if further optimization is required:
1) Does it fit correctly and are there truly any issues with belt alignment? Was the experience on the board just bad installation or a kit out of spec?

2) Is the fuel issue I read about really related to fuel pump capacity or is it just a question of the injectors being maxed out. If it's the former, surely a boost a pump would fix it. If it's the latter, than just swapping out for a set of slightly larger injector should remedy it.

3) Regarding the airflow dilemma: Just a quick comparison with the airbox installed and the airbox removed with just the TB and inlet tube should be able to give us at least the beginnings of an answer.

Given the great reputation of Whipple, it's interesting that we haven't had confirmation whether any of these issues are real issues or just anomalies.

Can anyone offer any insight??? Everything seems so secretive at the moment and none of these scenarios above are that complex or time consuming.

 

[Fubar]

1) I had no belt alignment issues. I have only heard about one installation having this problem. I suspect it is an isolated event.

2) I know my fuel pumps were working at 95% on my first tune (post whipple). I added the boost-a-pump and I am seeing 88% max duty cycle on the fuel pumps and 80% on the injectors. Both of these figures are high by my standards but not dangerous.

3) Airflow is always an issue, if you can free up the air you will get more power no matter what type of induction you are using. The airbox houses the MAF so it cannot be removed for testing. However you could remove the filters and see what that does you for you. I have not done this but I will when I have 'testing time.'

It is my opinion that the 4.0L brings the stock fuel system to its maximum horse power range. I don't think it is a problem with the whipple or the motor, it's just the nature of performance modifications. I suspect whipple (or somebody else) will introduce a modified airbox for the entire community to consider in the near future (within a year).

I hope that helps.

 

[lthlvpr]

Thanks for shedding some clarity on this.
I agree with you that these levels are not too high to be dangerous. I usually try to keep injectors and pump under 90% duty cycle.
1) Was the boost a pump a fairly easy install as on other cars? How much did you have to crank it up?
2) Do you think a boost a pump would still be necessary if had upgraded to larger injectors?
3) what power levels did you end up with (or increase over stock/over previous whipple..whatever your baseline was) and what pulley did you use and what octane are you tuned for?

Thanks!

 

[Black GT]

Would like to know about the above as well.

 

[lthlvpr]

Also, what ended up being the 'fix' or problem with those that were having boost levels drop after up shifting???

 

[dealmaker]

Also, what ended up being the 'fix' or problem with those that were having boost levels drop after up shifting???

I thought I was having this issue - turns out it was just the clutch struggling to cope and slipping! New clutch needed!

My 4.0L install went smoothly only problem is rear tire useage!

 

[Fubar]

Thanks for shedding some clarity on this.
I agree with you that these levels are not too high to be dangerous. I usually try to keep injectors and pump under 90% duty cycle.
1) Was the boost a pump a fairly easy install as on other cars? How much did you have to crank it up?
2) Do you think a boost a pump would still be necessary if had upgraded to larger injectors?
3) what power levels did you end up with (or increase over stock/over previous whipple..whatever your baseline was) and what pulley did you use and what octane are you tuned for?

Thanks!

1) I would not call it an easy install. Here are some pictures of the process. I am not sure would we turned it too. I will check on that and get back to you.
2) No, not required... yes for peace for mind. I think if I go with larger injectors I would also look at additional fuel pumps.
3)Stock the car made about 500whp. With pulley (17lbs), tune, headers and exhaust it made about 670whp. Then with the whipple (19lbs pulley) and tune it made about 780whp. All on 93 oct pump gas.

 

[Black GT]

Mine is making 743rwhp on 91 pump with a 20lbs on a 3.4L so we are talking about 40rwhp or so.

 

[Black GT]

Oh, stock manifolds......Heffner cat back

 

[Ed Sims]

air flow restriction

The heads/valves become a restriction after a while. I think this would help more than getting larger & larger superchargers.

Ed

 

[Namor]

I agree, its frustrating as I'd buy a 4ltr off whipple right now if you could buy an off the shelf solution to the fuelling issue mainly but also the air box restrictions.

Can't believe no one out there - Accufab, Rousch, or Whipple themselves or coming up with this. I'm sure I'd not be the only one in the queue.

Didn't Rich instal a set of GT500 injectors on his car to solve the fuelling problem. If this becomes the 'approved' fix I'd keen to follow suit.

again would love Whipple, Rousch, Accufab to jump in and tell us what we can do.

running the car lean or close to it sounds horrific to me.

 

[ChipBeck]

Solution.

Gentlemen,

Stock fuel system, no boost-a-pump, stock air box, safe conservative A/F ratios, and 900 RWHP with no cats on 93 octain. All for a slight additional charge. :thumbsup

Chip

 

[BlackICE]

Very nice Chip, but not an option for us poor suckers in Kalifornia with CARB regulations! I think the state's auto regulations are ran about as well as their finances.

 

[Shadowman]

Gentlemen,

Stock fuel system, no boost-a-pump, stock air box, safe conservative A/F ratios, and 900 RWHP with no cats on 93 octain. All for a slight additional charge. :thumbsup

Chip

She looks ..... "sweeet!!" ...... very

and yet the difference between the operational feel of the supercharger versus turbos is as night is to day. Both "bad to the bone" however one needs to decide the use of the gal and be honest about their driving style.

My vote for those that remain supercharged is 3.4 liter except for those that like and want to tinker as well as dealing with race fuels because without these/this the net benefit of the 4 liter is IMO a margin call at best.

Takes care

Shadowman

 

[lthlvpr]

My understanding is that Whipple is no longer offering the 3.4L kit for the GT, only the 4.0L. It sounded like they were also working on a new airbox and fueling solutions as well so they can offer a truly complete kit for the 4.0L unit. Maybe, they will have an update for us soon.

 

[w. mitty]

Guess that means my 3.4 liter is a collector's item now. Too bad I don't want to take it off the car...:biggrin

 

[w. mitty]

She looks ..... "sweeet!!" ...... very

and yet the difference between the operational feel of the supercharger versus turbos is as night is to day. Both "bad to the bone" however one needs to decide the use of the gal and be honest about their driving style

I've often pondered on the the way the two systems might feel comparatively. Tell me what your observations are regarding low end grunt--I surmise that there would be the inevitable lag with the turbo cars. Not a dig, but just wonder if it would detract from the feel of the stump pulling torque of the whipple? Having considered throwing down the cash to go turbo, I'd really like to hear your observations!

 

[Shadowman]

My understanding is that Whipple is no longer offering the 3.4L kit for the GT, only the 4.0L. It sounded like they were also working on a new airbox and fueling solutions as well so they can offer a truly complete kit for the 4.0L unit. Maybe, they will have an update for us soon.

FYI the 3.4 liter is still in production; I just had another one delivered a couple days ago.

Takes care

Shadowman