Help a VinC breathe better.... - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1987-1991 Parley with regards to your 1987 to 1991 Bonneville, Olds 88 or Buick Le Sabre Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 07-27-2004, 12:43 PM   #1
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Default Help a VinC breathe better....

Quote:
Originally Posted by jr's3800
I'll agree with Pagett here... The limitations on the C engines are mechanical.... I have had my 3800 Vin C apart to do the heads.... They are a good design, but were not built for performance... Just built to be good everyday drivers, and interstate cruisers... They do have plenty of low end torque... But like Padgett said, their inhailing ability is limited..

On another note, I have had my heads done, replaced all the lifters, I have NGK TR55 plugs, Taylor wires, and an intake... I had a Delco Type 2 ICM untill it fried... All of these items together seemed to make the most diffrence and was well worth my time and $$$..

They all of the small things first, swap to a Type II ignition system, then go with good wires, and a set of TR55 plugs, at the least invest in a K&N filter... Possibly a high flow Cat Converter... All of these should help you a bit...
I didn't want to hijack his post, so I thought I'd start another.
You guys said the problem w/ the VinC is it'* inability to inhale....

Where are the restrictions? What can be done to make it breathe better.
What is a "type II ignition system", how does that differ from the stock one?

Here'* what I've done thus far..

-K&N air filer
-redone my exhaust from the manifold back.. 2.5inchs... high flow cat w/ a mangaflow fbody exhaust.
-new/rebuilt transmission, with a shift kit
(I'm getting a CAI (probably a fender intake) done in the next few weeks.)



What else can I do to squeeze a little extra power out of her?
Or at least help her run better.
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Old 07-27-2004, 03:14 PM   #2
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Quote:
Originally Posted by jr's3800
On another note the intake runners on the Vin C engine aren't really tunned for it, But I still like the way mine runs... I will say that every L27 Tunned Port Injection engine I have ever seen revs better than ant vin C I have driven.. And the exactly what it is, the L27 has a tunned intake... Only good for 5 Hp though...( Not enough to make me buy one )..
Although you gain the 5 peak hp, do you gain favourable gains *across* the entire rev range? If so, it may be worthwhile in itself.


I've got just the K&N filter. Though any other mods/plans on my car may be gone out the window by now. I'm falling out of love with my car (still like other Bonnies in general). Rust, rust, rust galore, and now a potential tranny issue.
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Old 07-27-2004, 08:05 PM   #3
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a) no rust is one reason I live in Orlando (50 miles to nearest coast)
b) all of my cars are garaged - two in the front and three in the back - and natives always seek shade when parking elsewhere
c) I suspect that the 30% increased flow area around the throttle plate may have more to do with the 5 hp than the snakes. "L" is also cammed differently than "C". The longer runners are for low end improvements, not high.
d) first "L"* had the same minimal air filters as "C", later ones had a redesigned filter box and much more area. Has anyone ever taken an air box from say a 1999 Alero 3.4 and tried it on a Bonne ?
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Old 07-27-2004, 09:45 PM   #4
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Not at home as usual but believe the 88 cam had about 188 degrees at .050" on both intake and exhaust with a 110 degree separation. A different cam was used in 89-90 with (AFAIR) slightly shorter duration and more lift (might have that backwards).

Keep in mind that the 3800 has 1.6 rockers so a .250 lift at the cam translates to .400 at the valve. I would not want to add much more lift (spring bind) but think 205-210 degrees at .050" would be "better".

We discussed this extensively with Crane Cams when a friend converted a 3800 "C"/440T4 to 3800 "L"/Getrag 5-speed and decided on a H-264 grind with just slightly more lift (.410) and considerably more duration but still able to have a smooth idle and be controlled by the stock computer. Am not certain if this is still available (Greg had to supply a stock cam to be reground) but Lazer seems to have a few that are similar.

Keep in mind that first the "C" engine was designed for maximum torque at the most likely cruising speed (and the country had a 55 mph speed limit at the time so we should probably be glad we got as much cam as we did, even at 70 mph in o/d lockup it is barely at the 2000 rpm peak (some think that number is a mistake and should be 2800. T'aint. Just few remember the Nader of the 55 mph period when a SBC had a peak torque at 1800 rpm (1978 LG3).

Once the 55 mph limit went away (1995) the engines were redesigned for the expected use (70-75 mph) but even the 1991 "L" engine has the capabilitiy for a much better top end with both increased (30%) intake (anyone ever put a "L" MAF on a "C" manifold ?) and a cleaned up exhaust.

Might want to compare the peak torque rpm on pre- and post-1995 3800s at http://dtcc.cz28.com/gminfo.htm
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